808 research outputs found
Influence of the thermocline on the vertical migration of medusae during a 48 h sampling period
The vertical distribution and migratory movements of epiplanktonlc medusae were studied at an oceanic station off northern Namibia (18°00’S /10°30’E). Samples were collected from five separate depth strata (200–100 m, 100–60 m, 60–40 m, 40–20 m, and 20–0 m) using a multiple opening and closing RMT 1 x 6 net over a 48–h period. The area was characterized by mixing of the Angola Current surface waters with the northernmost subsurface waters of the Benguela Current. During the sampling period there was a continuous flow of water from Angola, giving rise to a strong thermocline between 20 and 40 m depth. A total of 17 species of medusae were captured, of which Aglaura hemistoma, Liriope tetraphylla, and Solmundella bitentaculata were the most abundant. Both the number of species and the number of individuals were higher on the second than on the first day of sampling, chiefly in the 20–0 stratum. Differences in abundance appeared to be related to the patch size of each species. The depth diistributlon of the medusae population was characterized by the existence of two assemblages, one associated with each current, and by the presence of the thermocline, which acted as a boundary between the two water masses and did not facilitate migratory movements of the most abundant species. The non-migratory distribution pattern of most of the species was attributable to the high concentration of potential prey items and to the absence of predators in the layer above the thermocline throughout the sampling period
Ceria-Based Dual-Phase Membranes for High-Temperature Carbon Dioxide Separation: Effect of Iron Doping and Pore Generation with MgO Template
Dual-phase membranes for high-temperature carbon dioxide separation have emerged as promising technology to mitigate anthropogenic greenhouse gases emissions, especially as a pre- and post-combustion separation technique in coal burning power plants. To implement these membranes industrially, the carbon dioxide permeability must be improved. In this study, Ce0.8Sm0.2O2−δ (SDC) and Ce0.8Sm0.19Fe0.01O2−δ (FSDC) ceramic powders were used to form the skeleton in dual-phase membranes. The use of MgO as an environmentally friendly pore generator allows control over the membrane porosity and microstructure in order to compare the effect of the membrane’s ceramic phase. The ceramic powders and the resulting membranes were characterized using ICP-OES, HSM, gravimetric analysis, SEM/EDX, and XRD, and the carbon dioxide flux density was quantified using a high-temperature membrane permeation setup. The carbon dioxide permeability slightly increases with the addition of iron in the FSDC membranes compared to the SDC membranes mainly due to the reported scavenging effect of iron with the siliceous impurities, with an additional potential contribution of an increased crystallite size due to viscous flow sintering. The increased permeability of the FSDC system and the proper microstructure control by MgO can be further extended to optimize carbon dioxide permeability in this membrane system.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli
Occlusion points identification algorithm
In this paper a very simple and efficient algorithm is proposed, to calculate the invisible regions of a
scene, or shadowed side of a body, when it is observed from a pre-set point. This is done by applying a
deterministic numerical procedure to the portion of scene in the field of view, after having been projected
in the observer reference frame. The great advantage of this approach is its generality and suitability for
a wide number of applications. They span from real time renderings, to the simulation of different types
of light sources, such as diffused or collimated, or simply to calculate the effective visible surface for a
camera mounted on board of an aircraft, in order to optimize its trajectory if remote sensing or aerial
mapping task should be carried out. Optimizing the trajectory, by minimizing at any time the occluded
surface, is also a powerful solution for a search and rescue mission, because a wider area in a shorter time
can be observed, particularly in situations where the time is a critical parameter, such as, during a forest
fire or in case of avalanches. For its simplicity of implementation, the algorithm is suitable for real time
applications, providing an extremely accurate solution in a fraction of a millisecond. In this paper, the
algorithm has been tested by calculating the occluded regions of a very complex mountainous scenario,
seen from a gimbal-camera mounted on board of a flying platform
Estudio cuantitativo y estacional de dos poblaciones de cnidarios planctónicos frente a las costas de Barcelona (Mediterráneo Occidental)
Incidence of colorectal cancer and influence of dietary habits in fifteen European countries from 1971 to 2002
AbstractObjectiveThis study aimed to analyze the incidence of colorectal cancer in 15 European countries in recent decades and the relationship between the incidence found and changes in dietary habits.MethodsPearson's or Spearman's correlation coefficients were calculated by comparing incidence rates obtained from the International Agency for Research on Cancer for 1971-2002 with data on per capita consumption obtained from the Food and Agriculture Organization of the United Nations using 10-year delay intervals.ResultsIncidence rates increased in all countries except France in men and except Austria, Denmark, England and France in women. Of the dietary variables considered, there were marked increasing trends (linear regression coefficient, R ≥0.5) in red meat consumption in Germany (R = 0.9), Austria (R = 0.7), Finland (R = 0.8), Italy (R = 0.9), Poland (R = 0.5), Spain (R = 2.1), Sweden (R = 0.6), and the Netherlands (R = 0.7).ConclusionsChanges in dietary habits may be consistent with the observed trends in the incidence of colorectal cancer in the distinct European countries
Brain connectivity changes after osteopathic manipulative treatment: A randomized manual placebo-controlled trial
The effects of osteopathic manipulative treatment (OMT) on functional brain connectivity in healthy adults is missing in the literature. To make up for this lack, we applied advanced network analysis methods to analyze resting state functional magnetic resonance imaging (fMRI) data, after OMT and Placebo treatment (P) in 30 healthy asymptomatic young participants randomized into OMT and placebo groups (OMTg; Pg). fMRI brain activity measures, performed before (T0), immediately after (T1) and three days after (T2) OMT or P were used for inferring treatment effects on brain circuit functional organization. Repeated measures ANOVA and post-hoc analysis demonstrated that Right Precentral Gyrus (F (2, 32) = 5.995, p < 0.005) was more influential over the information flow immediately after the OMT, while decreased betweenness centrality in Left Caudate (F (2, 32) = 6.496, p < 0.005) was observable three days after. Clustering coefficient showed a distinct time-point and group effect. At T1, reduced neighborhood connectivity was observed after OMT in the Left Amygdala (L-Amyg) (F(2, 32) = 7.269, p < 0.005) and Left Middle Temporal Gyrus (F(2, 32) = 6.452, p < 0.005), whereas at T2 the L-Amyg and Vermis-III (F(2, 32) = 6.772, p < 0.005) increased functional interactions. Data demonstrated functional connectivity re-arrangement after OMT
Sense of external agency is sustained by multisensory functional integration in the somatosensory cortex
Bats in urbanising landscapes: habitat selection and recommendations for a sustainable future
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