Современные тенденции развития рекреационного хозяйства в Украине

Chromiferous ultramafic rocks from Campo Formoso (Bahia State, Brazil) exhibit various stages of hydrothermal alteration and weathering, each being characterized by distinct chromiferous parageneses. These Cr-bearing minerals are mainly phyllosilicates, but other phases are also present as chromiferous opal and hydroxycarbonates. Optical absorption spectra and K-edge fine structure allow a better knowledge of chromium crystal chemistry in these minerals. The first stages of chromite oxidation have been precised, and particularly the influence of structural factors was pointed out : the inversion grade of these spinels controls the evolution from a mainly direct chromite to the inverse forms (ferritchromit). Chromium ions inserted in mineral structures do not exhibit any change in the oxidation state during alteration processes. In contrast, crystal field stabilization energy (CFSE) of Cr3+ ions exhibits important variations among the studied minerals. Study of EXAFS spectra demonstrated that Cr-O distances do not change significandy among the investigated minerals, the effective oxygen charge playing the main role in the observed CFSE variations. This latter parameter explains the concentration of chromium in these minerals and contributes to the stability of some phases like clinochlores and hydroxycarbonates, where trivalent chromium has the highest CFSE.Les ultrabasites chromifères de Campo Formoso (Etat de Bahia, Brésil) montrent plusieurs stades successifs d'altération hydrothermale puis superficielle qui s'accompagnent de paragenèses chromifères variées. Les minéraux caractéristiques de ces dernières sont essentiellement des phyllosilicates, mais on note aussi d'autres phases comme la stichtite et l'opale chromifère. Les spectres d'absorption X ont permis de caractériser la cristallochimie du chrome dans ces minéraux. Les premiers stades d'oxydation des chromites ont été précisés, en particulier l'influence de la structure réelle du spinelle (degré d'inversion) qui contrôle les conditions d'évolution de la chromite. Le degré d'oxydation +3 du chrome est conservé lors des processus d'altération et seule l'énergie de stabilisation liée au champ cristallin montre des changements importants. L'étude des spectres EXAFS (Extended X-ray Absorption Fine Structure) a montré que, les distances Cr-O ne changeant pas entre les minéraux étudiés, seule la nature des ligandes a une influence sur la valeur de l'énergie de champ cristallin. Ceci explique la forte concentration en chrome de ces minéraux d'altération et contribue à la stabilité des phases comme les clinochlores ou les hydroxycarbonates où les ions Cr3+ ont la plus forte énergie de stabilisation.Calas Georges, Manceau Alain, Novikoff André, Boukili Hassan. Comportement du chrome dans les minéraux d'altération du gisement de chromite de Campo Formoso (Bahia, Brésil). In: Bulletin de Minéralogie, volume 107, 6, 1984. pp. 755-766

Effects over one year of low-intensity endurance exercise targeted at the level of maximal lipid oxidation

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Possible Patient Early Diagnosis by Ultrasonic Noninvasive Estimation of Thermal Gradients into Tissues Based on Spectral Changes Modeling

To achieve a precise noninvasive temperature estimation, inside patient tissues, would open promising research fields, because its clinic results would provide early-diagnosis tools. In fact, detecting changes of thermal origin in ultrasonic echo spectra could be useful as an early complementary indicator of infections, inflammations, or cancer. But the effective clinic applications to diagnosis of thermometry ultrasonic techniques, proposed previously, require additional research. Before their implementations with ultrasonic probes and real-time electronic and processing systems, rigorous analyses must be still made over transient echotraces acquired from well-controlled biological and computational phantoms, to improve resolutions and evaluate clinic limitations. It must be based on computing improved signal-processing algorithms emulating tissues responses. Some related parameters in echo-traces reflected by semiregular scattering tissues must be carefully quantified to get a precise processing protocols definition. In this paper, approaches for non-invasive spectral ultrasonic detection are analyzed. Extensions of author's innovations for ultrasonic thermometry are shown and applied to computationally modeled echotraces from scattered biological phantoms, attaining high resolution (better than 0.1°C). Computer methods are provided for viability evaluation of thermal estimation from echoes with distinct noise levels, difficult to be interpreted, and its effectiveness is evaluated as possible diagnosis tool in scattered tissues like liver

On Limitations of the Ultrasonic Characterization of Pieces Manufactured with Highly Attenuating Materials

Some technical aspects of two Spanish cooperation projects, funded by DPI and Innpacto Programs of the R&D National Plan, are discussed. The objective is to analyze the common belief about than the ultrasonic testing in MHz range is not a tool utilizable to detect internal flaws in highly attenuating pieces made of coarse-grained steel. In fact high-strength steels, used in some safe industrial infrastructures of energy & transport sectors, are difficult to be inspected using the conventional “state of the art” in ultrasonic technology, due to their internal microstructures are very attenuating and coarse-grained. It is studied if this inspection difficulty could be overcome by finding intense interrogating pulses and advanced signal processing of the acquired echoes. A possible solution would depend on drastically improving signal-to-noise-ratios, by applying new advances on: ultrasonic transduction, HV electronics for intense pulsed driving of the testing probes, and an “ad-hoc” digital processing or focusing of the received noisy signals, in function of each material to be inspected. To attain this challenging aim on robust steel pieces would open the possibility of obtaining improvements in inspecting critical industrial components made of highly attenuating & dispersive materials, as new composites in aeronautic and motorway bridges, or new metallic alloys in nuclear area, where additional testing limitations often appear.The Spanish I+D National Plan (MINECO), by funding the Projects: Fundamental Research / DPI2011 – 22438, and INNPACTO Program / IMAAD - IPT-020000-2010-0004

Rearranging the centromere of the human Y chromosome with φC31 integrase

We have investigated the ability of the integrase from the Streptomyces φC31 ‘phage to either delete or invert 1 Mb of DNA around the centromere of the human Y chromosome in chicken DT40 hybrid somatic cells. Reciprocal and conservative site-specific recombination was observed in 54% of cells expressing the integrase. The sites failed to recombine in the remaining cells because the sites had been damaged. The sequences of the damaged sites indicated that the damage arose as a result of repair of recombination intermediates by host cell pathways. The liability of recombination intermediates to damage is consistent with what is known about the mechanism of serine recombinase reactions. The structures of the products of the chromosome rearrangements were consistent with the published sequence of the Y chromosome indicating that the assembly of the highly repeated region between the sites is accurate to a resolution of about 50 kb. Mini-chromosomes lacking a centromere were not recovered which also suggested that neo-centromere formation occurs infrequently in vertebrate somatic cells. No ectopic recombination was observed between a φC31 integrase attB site and the chicken genome