Geostatistical mapping and spatial variability of surficial sediment types on the Beaufort Sea shelf based on grain size data

The nearshore Beaufort Sea is a sensitive marine environment that is also the focus of oil and gas exploration. Offshore, the Beaufort Sea contains large potential reserves of hydrocarbons. Any future exploitation of these resources will present unique engineering challenges and will require an understanding of the processes that govern stability, nearshore morphology and sediment properties in the extensive shallow coastal zone of the Beaufort Sea shelf. Knowledge of the surficial sediment distribution is, therefore, necessary to provide a framework for understanding sediment stability, sediment transport, platform foundation conditions and to balance engineering challenges with environmental concerns, resource development and precautionary sustainable management. We describe an approach for a quality controlled mapping of grain sizes and sediment textures for the Beaufort Sea shelf in the Canadian Arctic. The approach is based on grain size data sampled during the period 1969-2008. A replenishment of grain size data since the 1980’s, as well as the consideration of correlating parameters (bathymetry, slope and sediment input) to a cokriging algorithm, amends the former way of mapping the surficial sediments of the Beaufort Sea shelf. Subsequent to data processing and applying autocorrelation, four single grids (clay, silt, sand and gravel) were generated from grain size data by ordinary kriging and cokriging. Cokriging also considered parameters that influence sediment texture such as bathymetry, slope, cost distance from the Mackenzie River and data anisotropy (directional dependency). The cokriging algorithm expressed as a variogram was quality controlled by cross-validation and predicted standard errors (PSEs). PSE values express a maximum deviation of modeled from the real values and therefore help to estimate the quality in these regions regarding the interpolation results for each grain size range. A sediment type classification scheme applied to the set of clay, silt, sand and gravel content maps resulted in a sediment type map of the Beaufort Sea shelf. The PSEs of ordinary kriging and cokriging have been compared and showed that the cokriging technique provided superior interpolation results for silt and slightly improved results for clay and sand. Cokriging was able to capture most of the small variations in the sediment texture distribution. Furthermore, reduced nugget effects confirmed that the cost distance grid was a better indicator for sediment texture when compared to bathymetry and slope. For gravel, ordinary kriging achieved better prediction probabilities and was, therefore, used for generation of the distribution map for this grain size class. The use of cokriging and ordinary kriging greatly enhanced interpolation estimates without additional sampling. Especially in nearshore regions, like the Beaufort Sea shelf, geostatistical interpolation techniques are very useful for evaluating seabed sediment texture because sampling is often difficult or impossible due to ice conditions or even prohibited near oil platforms. The described methodology along with the inclusion of recent data, provided an improved mapping of the surficial sediments of the Beaufort Sea shelf

Conjunctive queries with negation over DL-Lite: a closer look

While conjunctive query (CQ) answering over DL-Lite has been studied extensively, there have been few attempts to analyse CQs with negated atoms. This paper deepens the study of the problem. Answering CQs with safe negation and CQs with a single inequality over DL-Lite with role inclusions is shown to be undecidable, even for a fixed TBox and query.Without role inclusions, answering CQs with one inequality is P-hard and with two inequalities CoNP-hard in data complexity

Contrasting spatial heterogeneity of sessile organisms within mussel (Perna perna L.) beds in relation to topographic variability

We examined the spatial heterogeneity in three sessile rocky shore organisms, the mussel Perna perna, the barnacle Octomeris angulosa (Sowerby) and the red alga Gelidium pristoides (Turn.) at a range of continuous local scales along horizontal transects within mid- and upper mussel beds of South African shores. We also examined the relationships between variability of organisms and topographic features (rock depressions, slope, aspect), and between mussel, barnacle and algal variability over the same scales. To estimate spatial heterogeneity, we analyzed scaling properties of semivariograms using a fractal approach. Relationships between different variables at the different scales were examined by cross-semivariograms. Spatial dependence of P. perna variability increased with spatial dependence of topographic variability, so that scaling regions of mussel and topographic distributions corresponded well. This relationship often improved with larger local scales (mussel cover increased with depressions, steeper slope and aspect towards waves), while at smaller spatial scales, variability in mussel cover was less well explained by variability in topography. The variability of the barnacle O. angulosa exhibited spatial dependence, even on topographically unstructured shores. In contrast, the distribution of the alga G. pristoides revealed high fractal dimensions, showing spatial independence on topographically unstructured shores. Algae also showed a very strong negative relationship with mussels at most local scales, and a negative relationship with barnacles in upper zones, especially at larger local scales. Barnacles may show clear spatial dependence because of hydrodynamics (at larger local scales) and the need to find a future mate in close proximity (at smaller local scales), while algae may show a strong negative relationship with mussels because of competition for space

Micro-relief and roughness of the surface of the profiled sulfocation-exchange membrane after its contact with phenylalanine solution

The work was conducted under financial support of RFBR (project N 18-08-01260)

Direct Hopf Bifurcation in Parametric Resonance of Hybridized Waves

We study parametric resonance of interacting waves having the same wave vector and frequency. In addition to the well-known period-doubling instability we show that under certain conditions the instability is caused by a Hopf bifurcation leading to quasiperiodic traveling waves. It occurs, for example, if the group velocities of both waves have different signs and the damping is weak. The dynamics above the threshold is briefly discussed. Examples concerning ferromagnetic spin waves and surface waves of ferro fluids are discussed.Comment: Appears in Phys. Rev. Lett., RevTeX file and three postscript figures. Packaged using the 'uufiles' utility, 33 k

SCREENING OF RICE ACCESSIONS FOR GREENBUG RESISTANCE

During recent years the harmfulness of greenbug for rice crops has significantly increased. Laboratory experiments were conducted to study insect resistance of 200 accessions from the collection of the Donskoy Agrarian Scientific Center. The overwhelming majority of the studied forms were heterogeneous in their resistance. Twelve forms (5.5%) with the resistance score 2.2-3.0 were identified. The accessions NSH-1 (Hungary), ‘Musa Karem’ (Iran) and Zlatyi х Strelets (Russia) do not contain susceptible components and can be recommended as sources of aphid resistance for breeding rice varieties

СТРУКТУРНІ ТА ФУНКЦІОНАЛЬНІ ХАРАКТЕРИСТИКИ МІОКАРДУ У ДІТЕЙ З ТЕРМІНАЛЬНОЮ ХРОНІЧНОЮ НИРКОВОЮ НЕДОСТАТНІСТЮ НА ДІАЛІЗНОМУ ЛІКУВАННІ

Матеріал та методи. Проведено оцінку морфо-функціонального стану міокарду у 28 дітей з термінальною хронічною нирковою недостатністю, які знаходяться на діалізному лікуванні. Результати. Нормальна геометрія лівого шлуночку виявлена лише у 14,3% обстежених дітей. У 71,4% обстежених виявлено концентричну гіпертрофію лівого шлуночка (ЛШ), а у 10,7% - ексцентричну гіпертрофію ЛШ. Ознаки дисфункції серцевої діяльності виявленеі у 85,7% дітей, причому у 41,7% з них це супроводжується дилатацією порожнини лівого  шлуночку. Ознаки систолічної (СДЛШ) та діастолічної дисфункції лівого шлуночку (ДДЛШ) виявлено у 58,3% хворих з ремоделюванням лівого шлуночку. Значна дилатація ЛШ поєднувалася з розвитком СДЛШ у 54,5% пацієнтів та ДДЛШ - у 18,2% пацієнтів, що дозволяє вважати її маркером міокардіальної дисфункції у дітей з уремічною кардіоміопатією. Висновки. Концентричний варіант ремоделювання ЛШ у порівнянні з іншими є більш сприятливим та рідше супроводжується розвитком кардіальної дисфункції, якщо він не поєднується із значною дилатацією ЛШ

Resonant scattering of spin waves from a region of inhomogeneous magnetic field in a ferromagnetic film

The transmission of a dipole-dominated spin wave in a ferromagnetic film through a localised inhomogeneity in the form of a magnetic field produced by a dc current through a wire placed on the film surface was studied experimentally and theoretically. It was shown that the amplitude and phase of the transmitted wave can be simultaneously affected by the current induced field, a feature that will be relevant for logic based on spin wave transport. The direction of the current creates either a barrier or well for spin wave transmission. The main observation is that the current dependence of the amplitude of the spin wave transmitted through the well inhomogeneity is non-monotonic. The dependence has a minimum and an additional maximum. A theory was constructed to clarify the nature of the maximum. It shows that the transmission of spin waves through the inhomogeneity can be considered as a scattering process and that the additional maximum is a scattering resonance