Методы добычи сланцевого газа и их воздействие на окружающую среду

We have studied GaAs/AlGaAs- and GaAs/AlAs-samples grown by molecular beam epitaxy by X-ray scattering under grazing angles to investigate surface and interface roughness. We discuss the reliability of buried interface roughnesses derived from fits to specular reflectivity by means of a sample series grown at substrate temperatures from 605 to 685°C. Even for samples of high perfection no abrupt interfaces were found. We have applied this method to the problem of growth-induced roughening of GaAs- and AlAs-layers. Sample series with increasing film thickness between 50 and 2000 Å for AlAs and 5000 Å for GaAs have been investigated. We observe roughening which in the case of AlAs does not follow a power law expected within the framework of kinetic roughening theory. However, for GaAs the data can be described by a very small growth exponent β = 0.11 ± 0.03

Genetic and metabolic links between the murine microbiome and memory.

BackgroundRecent evidence has linked the gut microbiome to host behavior via the gut-brain axis [1-3]; however, the underlying mechanisms remain unexplored. Here, we determined the links between host genetics, the gut microbiome and memory using the genetically defined Collaborative Cross (CC) mouse cohort, complemented with microbiome and metabolomic analyses in conventional and germ-free (GF) mice.ResultsA genome-wide association analysis (GWAS) identified 715 of 76,080 single-nucleotide polymorphisms (SNPs) that were significantly associated with short-term memory using the passive avoidance model. The identified SNPs were enriched in genes known to be involved in learning and memory functions. By 16S rRNA gene sequencing of the gut microbial community in the same CC cohort, we identified specific microorganisms that were significantly correlated with longer latencies in our retention test, including a positive correlation with Lactobacillus. Inoculation of GF mice with individual species of Lactobacillus (L. reuteri F275, L. plantarum BDGP2 or L. brevis BDGP6) resulted in significantly improved memory compared to uninoculated or E. coli DH10B inoculated controls. Untargeted metabolomics analysis revealed significantly higher levels of several metabolites, including lactate, in the stools of Lactobacillus-colonized mice, when compared to GF control mice. Moreover, we demonstrate that dietary lactate treatment alone boosted memory in conventional mice. Mechanistically, we show that both inoculation with Lactobacillus or lactate treatment significantly increased the levels of the neurotransmitter, gamma-aminobutyric acid (GABA), in the hippocampus of the mice.ConclusionTogether, this study provides new evidence for a link between Lactobacillus and memory and our results open possible new avenues for treating memory impairment disorders using specific gut microbial inoculants and/or metabolites. Video Abstract

Emerging IT risks: insights from German banking

How do German banks manage the emerging risks stemming from IT innovations such as cyber risk? With a focus on process, roles and responsibilities, field data from ten banks participating in the 2014 ECB stress test were collected by interviewing IT managers, risk managers and external experts. Current procedures for handling emerging risks in German banks were identified from the interviews and analysed, guided by the extant literature. A clear gap was found between enterprise risk management (ERM) as a general approach to risks threatening firms’ objectives and ERM’s neglect of emerging risks, such as those associated with IT innovations. The findings suggest that ERM should be extended towards the collection and sharing of knowledge to allow for an initial understanding and description of emerging risks, as opposed to the traditional ERM approach involving estimates of impact and probability. For example, as cyber risks emerge from an IT innovation, the focus may need to switch towards reducing uncertainty through knowledge acquisition. Since individual managers seldom possess all relevant knowledge of an IT innovation, various stakeholders may need to be involved to exploit their expertise

EXAFS STUDY ON RADIATION INDUCED DEFECTS

No abstract availabl

SURFACE ORDER-DISORDER TRANSITION IN THE SOLID SOLUTION Cu3 Au

La criticalité superficielle d'un système semi-infini qui subit une transformation des phases de première espèce est considérée. Nous présentons la diffusion des rayons X-Synchrotron sur la surface (100) de la superstructure d'alliage Cu3Au ordonné, la sensitivité superficielle étant accomplie par la réflexion totale. La dépendance de l'intensité (001) évanescente en fonction de la température et de la profondeur de diffusion est analysée quantitativement et on montre que le paramètre d'ordre superficiel disparaît continûment et qu'une couche de mouillage désordonnée existe près de la température de transition T0. Les observations sont en accord avec la supposition d'une croissance logarithmique de cette région désordonnée de surface en approchant T0.Surface criticality of semi-infinite systems which undergo first order phase transitions is considered. We present Synchrotron-X superlattice scattering intensities from the Cu3Au(100) surface, where the surface sensitivity is achieved by the scheme of total external reflection. The quantitative analysis of the temperature- and scattering depth-dependence of the evanescent (001) superlattice peak proofs the continous behaviour of the surface order parameter and the existence of a disordered "wetting layer" below the transition temperature T0. The observations are consistent with the assumption of a logarithmic growth of this surface-induced disordered region when T0 is approached

Shift of the Bragg position in grazing-incidence diffraction

The intensity distribution in grazing-incidence diffraction along the grazing exit angle, a f, has been generally studied assuming the fulfilment of the Bragg condition, both experimentally and theoretically. We consider deviations of the incidence angle and detector position (θ) from the exact Bragg angle, θB, as well as variation of the incidence angle with respect to the surface, αi, and lattice mismatching of layered structures. The so-called surface peak is caused by refraction and appears at the fixed angular position of the critical angle of the total external reflection, αc. Beside it an additional peak occurs, that is explained by fulfilling the Bragg condition of the lateral wave vector components of incident and diffracted beams. This corresponds to the intersection of the truncation rod and the Ewald sphere. Therefore its angular position in the diffracted scattering fan depends on both αi and θ − θB. This additional peak is only visible if αi is below αC or θ > θB. These considerations have been verified experimentally on an InP layer