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The southeast Pacific Ocean is covered by the world's largest stratocumulus cloud layer, which has a strong impact on ocean temperatures and climate in the region. The effect of anthropogenic sources of aerosol particles on the stratocumulus deck was investigated during the VOCALS field experiment. Aerosol measurements below and above cloud were made with a ultra-high sensitivity aerosol spectrometer and analytical electron microscopy. In addition to more standard in-cloud measurements, droplets were collected and evaporated using a counterflow virtual impactor (CVI), and the non-volatile residual particles were analyzed. Many flights focused on the gradient in cloud properties on an E-W track along 20° S from near the Chilean coast to remote areas offshore. Mean statistics, including their significance, from eight flights and many individual legs were compiled. Consistent with a continental source of cloud condensation nuclei, below-cloud accumulation-mode aerosol and droplet number concentration generally decreased from near shore to offshore. Single particle analysis was used to reveal types and sources of the enhanced particle number that influence droplet concentration. While a variety of particle types were found throughout the region, the dominant particles near shore were partially neutralized sulfates. Modeling and chemical analysis indicated that the predominant source of these particles in the marine boundary layer along 20° S was anthropogenic pollution from central Chilean sources, with copper smelters a relatively small contribution. Cloud droplets were smaller in regions of enhanced particles near shore. However, physically thinner clouds, and not just higher droplet number concentrations from pollution, both contributed to the smaller droplets. Satellite measurements were used to show that cloud albedo was highest 500–1000 km offshore, and actually slightly lower closer to shore due to the generally thinner clouds and lower liquid water paths there. Thus, larger scale forcings that impact cloud macrophysical properties, as well as enhanced aerosol particles, are important in determining cloud droplet size and cloud albedo. Differences in the size distribution of droplet residual particles and ambient aerosol particles were observed. By progressively excluding small droplets from the CVI sample, we were able to show that the larger drops, some of which may initiate drizzle, contain the largest aerosol particles. Geometric mean diameters of droplet residual particles were larger than those of the below-cloud and above cloud distributions. However, a wide range of particle sizes can act as droplet nuclei in these stratocumulus clouds. A detailed LES microphysical model was used to show that this can occur without invoking differences in chemical composition of cloud-nucleating particles.

We present a new planar Ni compound refractive lens for high energy X-rays (116 keV). The lens is composed of identical plano-concave elements with longitudinal parabolic grooves manufactured by a punch technique. In order to increase the lens transmission, the thickness of the single lens at the parabolic groove vertex was reduced to less than 5 μm and the radius of curvature was reduced to about 20 μm. The small radius of curvature allowed us to reduce the number of single elements needed to get the focal length of 3 m to 54 single lenses. The gain parameter has been significantly improved compared to the previous lenses due to higher transmission, but the focused beam size and its gain are not as good as expected, mostly due to the aberrations caused by the lens shape imperfections.

The theory of stochastic condensation, which models the impact of an ensemble of unresolved supersaturation fluctuations S′ on the volume-averaged droplet-size distribution f (r), is revisited in the modern context of subgrid cloud parameterization. The exact transition probability density for droplet radius driven by independent, Gaussian S′ fluctuations that are periodically renewed is derived and shown to be continuous but not smooth. The Fokker–Planck model follows naturally as the smooth-in-time approximation to this discrete-in-time process. Evolution equations for the moments of f (r) that include a contribution from subgrid S′ fluctuations are presented; these new terms are easily implemented in moment-based cloud schemes that resolve supersaturation. New, self-consistent expressions for the evolution of f (r) and mean supersaturation S in a closed, adiabatic volume are derived without approximation; quite appropriately, these coupled equations exactly conserve total water mass. The behavior of this adiabatic system, which serves as a surrogate for a closed model grid column, is analyzed in detail. In particular, a new nondimensional number is derived that determines the relative impact of S′ fluctuations on droplet spectral evolution, and the contribution of fluctuations to S is shown to be negative definite and maximal near the accommodation length and has a direct correspondence to the analysis of Cooper. Observational support for the theory of stochastic condensation is found in cloud droplet spectra from cumulus cloud fields measured during the Rain in the Cumulus over the Ocean (RICO) and Small Cumulus Microphysics Study (SCMS) campaigns. Increasing spectral broadening with increasing spatial scale is discovered and compares well with theoretical predictions. However, the observed spectra show evidence of non-Gaussian S′ fluctuations and inhomogeneous mixing, processes neglected in the current theory.

In this manuscript - which closely follows Jeffery et al. (2006) - we have taken "another look" at stochastic condensation in the hope of clarifying the earlier derivations and fully exploring the implications of this theory. In contrast to the derivations of Levin and Sedunov (1966a, b) and Manton (1979), we begin with a simple model of stochastic condensation - independent, Gaussian supersaturation fluctuations (S′) renewed after a time τ - that is exactly solvable. This model is trivial to simulate on a computer and can be used to compare and contrast Lagrangian and Eulerian approaches for modeling droplet spectra (Andrejczuk et al. 2006). The Fokker-Planck approximation to this exact solution follows by replacing the discrete sampling of S′ with its continuous surrogate. The Fokker-Planck diffusivity and operator are thus seen to be the natural smooth-in-time approximation to a discrete-in-time process. We have also taken another - look at the equation for the mean supersaturation, S̄FP, in the presence of S′ fluctuations modeled using the Levin-Sedunov-Mazin Fokker-Planck operator. While this problem is treated in an approximate fashion (and with little transparency) in Voloshchukand Sedunov (1977), we derive the expression for (S′|r)FP without approximation and show how this expression "closes" the S̄FP-equation self-consistently, thereby ensuring that total water mass is exactly conserved. Using the quasi-stationary (QS) evaluation of S̄FP, we derive the exact correction term to SFP, QS (i.e. the S′ contribution corresponding to the Levin-Sedunov-Mazin model). The correction term is negative definite, peaks in magnitude when (r)r is near the accommodation length (≈ 2 μm), and decays as (r-1)r as the droplet spectrum grows to large sizes. This exact result has a direct correspondence to the analysis of Cooper (1989). Using our self-consistent equation for S̄FP, we evaluate spectral broadening in an adiabatic parcel and find some broadening to larger sizes (consistent with earlier estimates, e.g. Manton (1979)), but a more significant decrease in 〈r2〉 r at fixed liquid water content which may have implications for modeled cloud reflectivity. While the proceeding discussion is largely a clarification and elucidation of previous work, most notably Voloshchuk and Sedunov (1977), we have also extended the theory of stochastic condensation by deriving the non-dimensional number, ND, that determines the relative impact of S′-fluctuations on droplet spectral evolution in an adiabatic volume and in the QS limit. For constant updraft velocity and Fokker-Planck diffusivity, ND is also a constant, ranging from 10-2 to 102 for typical atmospheric conditions and model grid sizes when the assumed S′-standard deviation is 1%. We find significant spectral broadening, and in particular decreasing 〈r2〉r, for ND > 1, and discover that S̄FP, QS can be negative in a rising adiabatic parcel when ND > 6.5 for droplets of zero initial size. Using in-situ droplet spectra from cumulus cloud fields observed during the RICO and SCMS field campaigns, we have verified a seminal prediction of the theory of stochastic condensation - increasing broadening with increasing spatial scale - by averaging the observed spectra over segments containing one or more clouds. In addition, scale-dependent values of ND retrieved from the segment-averaged spectra using our adiabatic model show good consistency with the previously discussed theoretical estimates. We believe this encouraging result to be the first observational confirmation of the stochastic condensation mechanism and the decades-old, pioneering work of Levin-Sedunov-Mazin. Moreover, these results suggest that the parameterization of unresolved S′-fluctuations using Fokker-Planck theory or other means will become increasingly important as explicit (bin) microphysics schemes are applied at larger scales (Lynn et al. 2005), where an increasing fraction of individual clouds are, themselves, unresolved. However, important differences between the observed and modeled droplet spectra are also observed. In particular, the observed spectra suggest non-Gaussian S′ fluctuations and the inhomogeneous mixing process of Baker et al. (1980). Further work is needed to assess the impact of non-Gaussian S′-fluctuations and large renewal times on droplet spectral broadening and to derive differential operators that can model their ensemble effect in the equations of cloud physics.

Lagrangian Cloud Model (LCM) is a mixed Eulerian/Lagrangian approach to atmospheric large eddy simulation (LES), with two-way coupling between Eulerian dynamics and thermodynamics and Lagrangian microphysics. Since Lagrangian representation of microphysics does not suffer from numerical diffusion in the radius space and solves full droplet growth equations, it may be considered an alternative for the bin approach. This paper documents the development of LCM to include collision/coalescence processes. The proposed algorithm maps Lagrangian parcels collision/coalescence events on the specified two-dimensional grid, with the first dimension spanning aerosol radius and the second dimension spanning the cloud droplet radius. The proposed approach is capable of representation of aerosol activation, deactivation, transport inside the droplets, and processing by clouds and in the future may be used to investigate details of these processes. As an illustration, LCM with collision/coalescence is used to investigate effects of aerosols on cloud microphysics and dynamics for a marine stratocumulus cloud. Two extreme cases are considered that represent low and high aerosol concentrations. It is shown that the aerosol type significantly affects cloud microphysics as well as cloud dynamics. In agreement with previous studies, a larger entrainment rate is simulated for the high aerosol concentration. For the low aerosol concentration, intense collision/coalescence and drizzle modify the aerosol size distribution, reducing the concentration in the dry radius range of 0.02 to 0.2 m and increasing the concentration for dry radii larger than 0.3 m. © Copyright 2010 by the American Geophysical Union.

Small-scale mixing between cloudy air and unsaturated clear air is investigated in numerical simulations and in a laboratory cloud chamber. Despite substantial differences in physical conditions and some differences in resolved scales of motion, results of both studies indicate that small-scale turbulence generated through cloud-clear air interfacial mixing is highly anisotropic. For velocity fluctuations, numerical simulations and cloud chamber observations demonstrate that the vertical velocity variance is up to a factor of two larger than the horizontal velocity variance. The Taylor microscales calculated separately for the horizontal and vertical directions also indicate anisotropy of turbulent eddies. This anisotropy is attributed to production of turbulent kinetic energy (TKE) by buoyancy forces due to evaporative cooling of cloud droplets at the cloud-clear air interface. Numerical simulations quantify the effects of buoyancy oscillations relative to the values expected from adiabatic and isobaric mixing, standardly assumed in cloud physics. The buoyancy oscillations result from microscale transport of liquid water due to the gravitational sedimentation of cloud droplets. In the particular modeling setup considered here, these oscillations contribute to about a fifth of the total TKE production. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

With massive open on-line courses (MOOCs) gaining momentum, it is now common for thousands of students to enrol in a course, making manual assessments by teachers simply unfeasible. Peer assessments is one way to go when auto-scoring approaches are not possible. Current on-line courses usually use a simple aggregation of peer assessments, but these suffer from two main pitfalls. First, simple aggregation does not take into consideration the reliability of a peer assessment. Second, simple aggregation calculates what the students think of an assignment as opposed to what the teacher thinks of it (the far more important opinion). This work proposes two different models to address these two different pitfalls. These models lay the foundation for future work, where we intend to combine both models into a single one that addresses both pitfalls at once. The aim is to build an automated assessment system that results from the collaboration of both students and teachers., The second author is supported by an Industrial PhD scholarship from the Generalitat de Catalunya. Furthermore, this work is supported by the Gencat 2014 SGR 118 project (funded by the Generalitat de Catalunya), and the Collective-Mind and Collectiveware projects (funded by the Spanish Ministry of Economy and Competitiveness, under grant numbers TEC2013-49430-EXP and TIN2015-66863-C2-1-R, respectively).

[EN] Effective teams are crucial for organisations, especially in environments that require teams to be constantly created and dismantled, such as software development, scientific experiments, crowd-sourcing, or the classroom. One of the key factors influencing team performance is the personality of team members. In this paper, we introduce a new algorithm to partition a group of individuals into gender and psychologically-balanced problem-solving teams. With this purpose, we got inspiration from Wildes post-Jungian theory for team formation. Personality traits of people are obtained through a quantitative transformation of the Myers-Briggs Type Indicator (MBTI). The algorithm uses a greedy technique to balance the psychological traits of the members of teams so that each team gets the full range of problem-solving capabilities. Finally, we present some preliminary empirical results comparing the quality of the teams obtained by our algorithm and those proposed by a teacher., This work is supported by the CollectiveMind project (funded by the Spanish Ministry of Economy and Competitiveness, under grant number TEC2013- 49430- EXP) and the Collectiveware project (TIN2015-66863-C2-1-R). The first author is supported by an Industrial PhD scholarship from the Generalitat de Catalunya. We thank Rosa Maria Duran, tutor of group ‘3r B’, and Júlia Andrés, tutor of group ‘2n A’, for their collaboration in the evaluation of the method.

Proceedings of the 12th International Conference on X-Ray Microscopy, XRM 2014, Melbourne, Australia, 26 Oct 2014 - 31 Oct 2014 ; AIP conference proceedings 1696, 020049 (2016). doi:10.1063/1.4937543, Multilayer Laue lenses (MLLs) capitalize on the developments in multilayer deposition technologies for fabricating reflective coatings, specifically undertaken for EUV lithography, where layer thicknesses of several nanometers can be achieved. MLLs are deposited layer by layer, with their thicknesses following the zone plate law, and then pieces are sliced and extracted for use in focusing. Rays are reflected in the Laue geometry. The efficiency of a MLL can be very high, and is maximized by making the slice equal to about a half Pendellosung period so that most energy is transferred from the undiffracted to the diffracted beam, and by ensuring that the Bragg condition is met at each point in the zone plate. This latter condition requires that the layers are tilted to the beam by an amount that varies with layer position; e.g. for focusing a collimated beam, the layers should be normal to a cylinder of radius of twice the focal length. We have fabricated such tilted-zone MLLs and find that they exhibit improved efficiency across their entire pupil as compared with parallel-zone MLLs. This leads to a higher effective NA of the optic and hence higher resolution., Published by Inst., Melville, NY

This paper presents application of the Weather Research and Forecasting (WRF) model to limited-area modeling of atmospheric processes over the subtropical south-eastern Pacific, with the emphasis on the stratocumulus-topped boundary layer. The simulations cover a domain from the VAMOS (Variability of the American Monsoon Systems) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) field project conducted in the subtropical south-eastern Pacific in October and November 2008. We focus on a day where the UK's BAe-146 research aircraft encountered Pockets of Open Cells (POCs) at the very western edge of its flight track, rather than on the entire campaign as investigated in previous limited-area modeling studies. Model results are compared to aircraft observations with the main conclusion that the simulated stratocumulus-topped boundary layer is significantly too shallow. This appears to be a combination of an already too shallow boundary layer in the dataset used to provide initial and lateral boundary conditions, and the inability of the WRF model to increase the boundary-layer height. Several sensitivity simulations, applying different subgrid-scale parameterizations available in the model, a larger computational domain and longer simulations, as well as a different dataset providing initial and lateral boundary conditions were all tried to improve the simulation. These changes appeared to have a rather small effect on the results. The model does simulate the formation of mesoscale cloud-free regions that one might consider similar to Pockets of Open Cells observed in nature. However, formation of these regions does not seem to be related to drizzle-induced transition from open- to closed-cell circulations as simulated by LES models. Instead, the cloud-free regions appear to result from mesoscale variations of the lower-tropspheric vertical velocity. Areas of negative vertical velocity with minima (a few cm s−1) near the boundary layer top seem to induce direct evaporation of the cloud layer. It remains to be seen in LES studies whether the mechanism seen in the model is realistic or if it is simply an artifact of interactions between resolved and parameterized processes.

The electronic structure of divalent hexagonal close packed Mg is investigated by means of the high-resolution Compton scattering. Two-climensional (2D) electron momentum densities are reconstructed using their line integrals, derived from the plane integrals of three-dimensional (3D) electron momentum densities measured directly in the Compton experiment. The analysis is performed both in the extended and reduced zone schemes. The results are compared with corresponding densities calculated within Korringa―Kohn―Rostoker in the local density approximation (KKR-LDA) band structure theory and electron―positron densities measured in the angular correlation of annihilation radiation (ACAR) experiment.

The propagation of X-rays through a compound refractive lens (CRL) with imperfect CRL elements is investigated. The trajectories of random rays within the geometrical optics regime are calculated in one plane using Monte Carlo methods. Three different lenses were simulated: Be, Al and Ni lenses designed for photon energies of 20 keV, 60 keV and 175 keV, respectively. The results show that while transverse displacements of single elements in a CRL do not influence imaging resolution, rotational errors can be important. Systematic calculations of aberrations owing to the deviation of the element's surface from a perfect parabolic shape are also presented.

Enterprises frequently employ Corporate Social Responsibility (CSR) to create a positive brand image in the media. To further good relations with stakeholders, companies create an image before their customers by their participation in public campaigns and information in advertisements employing elements of CSR. Discussing this practice, I will highlight aspects of this phenomenon in the context of consumer opinion about advertisements. Some examples of companies show that Cause Related Marketing (CRM) and public campaigns are becoming more significant in the strategies of cause related companies. Enterprises at all costs want to buy their way into the favour of stakeholders, and through various marketing actions they try to build a strong brand and position in this way. In spite of the low evaluation of advertisements and the decline in confidence in them, enterprises aim to convince everyone that they are socially responsible companies.

This note presents an analysis of several dozens of direct numerical simulations of the cloud–clear air mixing in a setup of decaying moist turbulence with bin microphysics. The goal is to assess the instantaneous relationship between the homogeneity of mixing and the ratio of the time scales of droplet evaporation and turbulent homogenization. Such a relationship is important for developing improved microphysical parameterizations for large-eddy simulation of clouds. The analysis suggests a robust relationship for the range of time scale ratios between 0.5 and 10. Outside this range, the scatter of numerical data is significant, with smaller and larger time scale ratios corresponding to mixing scenarios that approach the extremely inhomogeneous and homogeneous limits, respectively. This is consistent with the heuristic argument relating the homogeneity of mixing to the time scale ratio.

Moderately porous Y-TZP dental ceramics were designed to combine the high strength and fracture toughness of densely sintered Y-TZP and the relatively low elastic modulus of porous Y-TZP ceramics. The materials were produced by biscuit-sintering dry-pressed pellets at different temperatures in an ambient air atmosphere. The flexural strength progressively increased with the fractional density, starting from 150–200 MPa at 55–60 % of theoretical density (TD), and exceeding 500 MPa at >80 % TD. The elastic modulus of the early-stage sintered material was matched with that of dentine, but the flexural strength was too low for a practical application. Strength values equal to or higher than those of the existing dental glass-ceramics and glass-infiltrated ceramic materials were achieved with specimens sintered to 8085 % TD, but the elastic modulus of these ceramics (100130 GPa) was about two times higher than that of dentine. Soft grinding of the biscuit-sintered samples resulted in a noticeable increase in the surface roughness, also leading to a significant strength reduction.

Compton profiles of hexagonal structure metals (Mg, Zn and Cd) were measured using high energy (662 keV – 137 Cs isotope gamma source) and medium resolution (0.4 a.u.) Compton spectrometer in the Institute of Experimental Physics, University of Bialystok. The experimental data were compared with corresponding first principles Korringa–Kohn–Rostoker coherent potential approximation calculations (KKR-CPA). Small anisotropy of Compton profiles measured in all three metals makes the observation of fermiological features extremely difficult. We show that to achieve this goal, high-resolution experimental data are essential. Judging from the recently obtained results for a much easier case of cubic Ni 75 Cu 25 and Ni 75 Co 25 alloys, one needs the resolution to be below about 0.15 a.u. Such an experiment can be carried out at the synchrotron radiation source only with the energy above 40 keV.

Previous studies indicate that the quality of single photon emission tomography/computed tomography (SPET/CT) myocardial perfusion imaging (MPI) is degraded by even mild transmission-emission misregistrations. The purpose of the current study was to investigate the impact of SPET/CT misalignment on the interpretation of MPI and examine the value of a commercial software application for registration correction.A total of 255 technetium-99m ((99m)Tc)-tetrofosmin stress/rest MPI examinations in 150 patients were reviewed for SPET/CT misalignment. After registration correction by the software, images were reassessed for interpretation differences from the misregistered study. The diagnostic benefit of reregistration was determined by taking into account the non-attenuation compensated image pattern, combined stress-rest evaluation, gated-SPET data and patient's history. In a phantom experiment and in 3 representative clinical cases, SPET/CT misalignment was purposely created by the software by sequential slice shifts and its effect was evaluated quantitatively.Misregistration ≥1 pixel in at least one direction was observed in 24% of studies. Interpretation of MPI changed after registration correction in 11% of cases with misalignment1 pixel, in 18% with 1-2 and in 73% with ≥2 pixels. The diagnostic information seemed to improve after registration correction in 58% of studies irrespective of the degree of misregistration. Software-simulated misregistration had dissimilar effects in the phantom and the 3 selected clinical cases.The impact of SPET/CT misregistration on MPI interpretation although influenced by the degree and direction of slice misplacement, it is also case-specific and hardly predictable. Registration restoration by the software seems worthwhile regardless of misregistration magnitude.

We present a new method to fabricate wedged multilayer Laue lenses, in which the angle of diffracting layers smoothly varies in the lens to achieve optimum diffracting efficiency across the entire pupil of the lens. This was achieved by depositing a multilayer onto a flat substrate placed in the penumbra of a straight-edge mask. The distance between the mask and the substrate was calibrated and the multilayer Laue lens was cut in a position where the varying layer thickness and the varying layer tilt simultaneously satisfy the Fresnel zone plate condition and Bragg’s law for all layers in the stack. This method can be used to extend the achievable numerical aperture of multilayer Laue lenses to reach considerably smaller focal spot sizes than achievable with lenses composed of parallel layers.

The ever-increasing brightness of synchrotron radiation sources demands improved X-ray optics to utilise their capability for imaging and probing biological cells, nanodevices and functional matter on the nanometer scale with chemical sensitivity. Here we demonstrate focusing a hard X-ray beam to an 8 nm focus using a volume zone plate (also referred to as a wedged multilayer Laue lens). This lens was constructed using a new deposition technique that enabled the independent control of the angle and thickness of diffracting layers to microradian and nanometer precision, respectively. This ensured that the Bragg condition is satisfied at each point along the lens, leading to a high numerical aperture that is limited only by its extent. We developed a phase-shifting interferometric method based on ptychography to characterise the lens focus. The precision of the fabrication and characterisation demonstrated here provides the path to efficient X-ray optics for imaging at 1 nm resolution.

This paper extends the previously published numerical study of Andrejczuk et al. on microscale cloud–clear air mixing. Herein, the primary interest is on microphysical transformations. First, a convergence study is performed—with well-resolved direct numerical simulation of the interfacial mixing in the limit—to optimize the design of a large series of simulations with varying physical parameters. The principal result is that all conclusions drawn from earlier low-resolution (Δx = 10−2 m) simulations are corroborated by the high-resolution (Δx = 0.25 × 10−2 m) calculations, including the development of turbulent kinetic energy (TKE) and the evolution of microphysical properties. This justifies the use of low resolution in a large set of sensitivity simulations, where microphysical transformations are investigated in response to variations of the initial volume fraction of cloudy air, TKE input, liquid water mixing ratio in cloudy filaments, relative humidity (RH) of clear air, and size of cloud droplets. The simulations demonstrate that regardless of the initial conditions the evolutions of the number of cloud droplets and the mean volume radius follow a universal path dictated by the TKE input, RH of clear air filaments, and the mean size of cloud droplets. The resulting evolution path only weakly depends on the progress of the homogenization. This is an important conclusion because it implies that a relatively simple rule can be developed for representing the droplet-spectrum evolution in cloud models that apply parameterized microphysics. For the low-TKE input, when most of the TKE is generated by droplet evaporation during mixing and homogenization, an inhomogeneous scenario is observed with approximately equal changes in the dimensionless droplet number and mean volume radius cubed. Consistent with elementary scale analysis, higher-TKE inputs, higher RH of cloud-free filaments, and larger cloud droplets enhance the homogeneity of mixing. These results are discussed in the context of observations of entrainment and mixing in natural clouds.

Directional Compton profiles of single crystal of hcp magnesium have been measured with scattering vectors along the [10 10], [1120] and [0001] directions in reciprocal space (special directions ΓΜ, ΓΚ, ΓΑ) using high-energy (662 keV) gamma radiation from a 137Cs isotope source. The experimental data were compared with corresponding theoretical Korringa-Kohn-Rostoker (KKR) calculations. The directional difference profiles, both experimental (of medium resolution) and theoretical ones, show very small anisotropy of the electron momentum density in magnesium, 2-3 times lower than in zinc and cadmium single crystals, significantly lower than observed in cubic metals. This small directional effect is in good agreement with Compton 60-keV energy experiments and positron annihilation data presented by other authors.

For conventional wavelength (UV–vis–IR) lasers delivering radiation energy to the surface of materials, ablation thresholds, etch (ablation) rates, and the quality of ablated structures often differ dramatically between short (typically nanosecond) and ultrashort (typically femtosecon d) pulses. Various very short-wavelength (λ < 100 nm) lasers, emitting pulses with durations ranging from ∼10 fs to ∼1 ns, have recently been placed into routine operation. This has facilitated the investigation of how ablation characteristics depend on the pulse duration in the XUV spectral region. Ablation of poly(methyl methacrylate) (PMMA) induced by three particular short-wavelength lasers emitting pulses of various durations, is reported in this contribution. © 2005 Elsevier B.V. All rights reserved.

The influence of excitation density on luminescence decay in Y3Al5O12:Ce and BaF2 crystals at room temperature was investigated for the first time using pulsed free electron laser radiation in vacuum ultraviolet. Increased excitation density led to the remarkable shortening of luminescence decays with non-exponential behaviour in both crystals. The possible reasons for dramatic changes in the dynamics of electronic excitations in insulators excited by free electron laser radiation will be discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The directional electron momentum density distributions (Compton profiles) of single-crystal cadmium have been measured in transmission and reflection experimental geometries using high-energy (662 keV) gamma radiation from a 137Cs isotope source. Profiles along the [100] and [110] directions in reciprocal space were measured in both geometries, whereas only the transmission geometry was used for the measurements along the [001] direction. The experimental data have been compared with corresponding theoretical KKR semi-relativistic calculations. The directional difference profiles, both experimental and theoretical, show, similarly to other hexagonal systems, very small anisotropy of the electron momentum density in hexagonal cadmium, about 0.3%, i.e. less than half of that presented in the literature for cubic systems. Minor discrepancies between KKR calculations and experiment probably occur due to the necessity to introduce an anisotropic electron–electron correlation correction. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Ablation behavior of organic polymer (polymethylmethacrylate) and elemental solid (silicon) irradiated by single pulses of XUV radiation emitted from Z-pinch, plasma-focus, and laser-produced plasmas was investigated. The ablation characteristics measured for these plasma-based sources will be compared with those obtained for irradiation of samples with XUV radiation generated by a free-electron laser.

Risk stratification in heart failure (HF) patients is an important element for management. There are several risk stratification models that can be used to predict the prognosis of patients with HF, such as Aaronson's scale, CVM-HF (CardioVascular Medicine Heart Failure), the Seattle Heart Failure Model (SHFM) and the Munich score. These models fail to adequately address the impact of multiorgan dysfunction on prognosis. The classical Model for End-Stage Liver Disease (MELD) score consists of: total bilirubin, INR (international normalized ratio) and creatinine level. There are some modifications of the MELD scale: MELD-XI, which excludes the INR score; the mod-MELD score, in which INR is replaced with albumin levels; and MELD-Na, which consists of the bilirubin and creatinine levels, INR ratio and the sodium level. Therefore, the MELD score systems are markers of multisystem dysfunction (renal, cardiac, hepatic). It is important that they are composed of routinely collected laboratory measures which are easy to use.W etiologicznie i funkcjonalnie niejednorodnej grupie chorych z niewydolnością serca istotnym elementem postępowania jest stratyfikacja ryzyka. Istnieją liczne modele prognostyczne stosowane do oceny ryzyka u chorych z niewydolnością serca, takie jak: skala Aaronsona, skala CVM-HF (

The abandoned quarries can represents a valuable from the environment protection point of view objects. The article is devoted to Skitskiy gypsum quarry located in the canyon of the Dniester River (Western Ukraine), which for over 50 years functions in the mode of renaturalization. The geological, geomorphological (karstic-speleological) and landscape-ecological values of the quarry, their protection, as well as possible ways to use this object are characterized.

The author concentrates on the methodological bases of contemporary geography. According to his point of view, contemporary geography has been experienced an identity crisis. Based on the macroevolutionary conception, the author tries to find out the “comprehensive idea” of geography, identify its object and subject of its research, prove the fundamental character of geography as a science, consider it in the context of other “systemological” sciences and illustrate its theoretical (scientific, in terms of outlook) and practical significance.

Karst landscapes are very specific in terms of its natural characteristics: geology, relief, water circulation, vegetation and soils. The specificity is due to the presence in the landscape of “lower underground floor” in form of a network of canals, cavities and caves, closely associated with the terrestrial part of the landscape. The article analyzes the karst landscape as a binary geosystem, consisting of two subsystems: surface and underground. Interactions between two subsystems (exchange of material and energy) are the essence of functioning of karst landscape and are ʺresponsibleʺ for formation of its dynamic-evolutionary peculiarities and physiognomy.

Gypsum is a rock having a wide spread in the earth's crust and on its surface. Due to the specified usable values gypsum is a desired raw material, mostly mined in quarries. Gypsum belongs to karstic rocks and easily dissolves in water. Therefore, a series of gypsum rocks, lying close to the earth surface and gypsum massifs usually are strongly karstified. Gypsum quarries almost always expose the karstified interior of gypsum massifs, rich in various karst forms both karstic and paleokarstic, including caves. The latter are often large and represent a valuable or even unique natural formations, which should be taken under protection. Karst formations frequently determine the total value of gypsum quarries as geosites. In the article, the values of various gypsum quarries of Podilla and Bukovina resulting from karst formations, especially the caves, are shown, as examples.

We have measured the directional Compton profiles of a single crystal of hexagonal zinc along the [001], [100], [110] and [111] directions using high-energy (662 keV) gamma radiation from a 137Cs isotope source. The experimental data have been compared with the corresponding theoretical Korringa-Kohn-Rostoker semi-relativistic calculations. The theory slightly overestimates the electron momentum densities at low momenta regions for all measured profiles. The directional difference profiles, both experimental and theoretical, show very small anisotropy of the electron momentum density in hexagonal zinc, at most half of that presented in the literature for cubic systems.

Circularly polarized synchrotron radiation of energy 200 keV has been used to study the spin dependent electron momentum distributions in Fe3Al and Fe3Si single crystals at room temperature through magnetic Compton profile measurements. The experiments were carried out for the crystallographic directions [100], [110] and [111] in Fe3Si, and [100] and [111] in Fe3Al. These results show that there is a more significant negative conduction electron spin polarization in both alloys than neutron data indicate and it is similar to that in pure iron. The overall characteristics of the experimental magnetic Compton profiles, as well as directional anisotropies, were found to be qualitatively similar for both compounds; however the anisotropy is higher in the case of Fe3Si. The majority and minority spin band profiles have been extracted and show that large anisotropies are associated with the latter. Their calculated anisotropy at low momenta was fully confirmed. The ab initio KKR calculation reproduces the Fe3Si profiles relatively well, but a `fixed-spin moment approach' was needed in order to describe the Fe3Al spin density momentum distribution.

Directional Compton profiles of single crystals of bismuth, Bi[100], Bi[110] and Bi[111] have been measured with high accuracy for the first time using 662 keV γ-radiation from a 137Cs isotope source. Korringa-Kohn-Rostoker (KKR) semi-relativistic calculations were performed to calculate the theoretical electron momentum density distributions along the three main crystallographic directions. The calculated and measured Compton profiles agree very well in periodicity of the oscillatory character of directional Compton anisotropies whereas the predicted amplitude of the oscillations is twice that measured in the experiment. Die richtungsabh�ngigen Comptonprofile wurden erstmalig mit hoher Auflosung und mit Hilfe der 662 keV γ-Strahlung einer 137Cs Quelle fur einkristallines Bismut entlang der [100], [110] sowie [111]-Richtungen bestimmt. Zur Bestimmung der theoretischen Impulsdichteverteilung entlang der drei Hauptsymmetrieachsen des Kristalls wurden Rechnungen auf der Basis eines semi-relativistischen Korringa-Kohn-Rostoker Ansatzes durchgefuhrt. Die berechneten und gemessenen Comptonprofile stimmen im Bezug auf die Periodizitat der Oszillationen der richtungsabhangigen Comptonprofilanisotropie uberein, wahrend die vorhergesagte Amplitude der Oszillationen um einen Faktor zwei groser ist als die im Experiment gemessene.

The directional Compton profiles (CPs) of hcp single crystal of magnesium have been measured along [1 0 0], [1 1 0] and [0 0 1] directions using high-energy (115.6 keV) synchrotron radiation and high-resolution (0.12 a.u.) Compton spectrometer. The experimental data were compared with Korringa–Kohn–Rostoker (KKR) semi-relativistic calculations and previous medium-resolution (0.4 a.u.; 1 a.u.=1.9929×10 −24 kg m s −1 ) Compton measurements. Anisotropy of CPs shows good agreement with medium-resolution experimental data and KKR calculations. Theoretically predicted sharp fermiology-related features of the electron momentum density, not observed in the medium-resolution measurements, have also been confirmed.