Search results for "activities"
showing 10 items of 3552 documents
Mercury in fish products: what’s the best for consumers between bluefin tuna and yellowfin tuna?
2017
A total of 205 bluefin and yellowfin tuna samples were examined for mercury detection in order to verify possible differences and have a detailed risk assessment of the two tuna species. The results showed significant higher mercury concentration in muscle tissue of bluefin tuna respect yellowfin tuna (p < 0.001) with mean concentration of 0.84 mg/kg and maximum value of 1.94 mg/kg. These differences can be due the different biological and ecological aspects of the two tuna species and to different oceanographic aspects between Atlantic Ocean and Mediterranean sea. The results obtained in this study suggest an advisable containment of the sources of pollution and further studies on the c…
Yield behavior of magnetorheological suspensions
2003
The rheology of suspensions containing magnetic particles of micrometer size is strongly modified by the application of a magnetic field. We first describe a model experiment where the suspension is made of spheres of millimeter size and we show that the experimental dependence of the yield stress is well predicted by a non-affine model where the chains of particles break in the middle. Then we compare these predictions with some experimental results obtained on suspensions of carbonyl iron; it is shown that this model does not apply in this case. We propose a mechanism where after some friction on the walls the aggregates begin to rotate and break at a strain smaller than unity, due to the…
The role of age and emotional valence in word recognition: an ex-gaussian analysis
2015
[Otro] Cie¿om práce je posúdi¿ vplyv veku a emo¿nej valencie na znovupoznávanie slov v rámci ex-Gaussových distribu¿ných komponentov. Dvom vekovým skupinám sme administrovali test znovupoznávania slov, v ktorom sme manipulovali emo¿nou valenciou. U mladších respondentov sa prejavili štatisticky signifikantné rozdiely pri negatívnych slovách v experimentálnej podmienke a v podmienke s distrakciou. U starších respondentov sme v odpove¿ových ¿asoch nezistili jasnú tendenciu. Vzh¿adom na ex-Gaussovský parameter ¿, ktorý sa v literatúre ¿asto spája s nárokmi na pozornos¿, vekovo podmienené rozdiely v emo¿nej valencii nemali žiaden vplyv na negatívne slová. Ak sa zameriame na emo¿nú valenciu v ob…
"Table 2" of "Measurement of differential Z / gamma* + jet + X cross sections in p anti-p collisions at s**(1/2) = 1.96-TeV"
2008
Measured cross section as a function of the jet rapidity.
Diapausing egg banls, lake size, and genetic diversity in rotifer Brchionus plicatilis Müller (Rotifera, Monogononta)
2017
Diapausing egg banks are reservoirs of ecological and genetic diversity in continental zooplankton. However, although habitat size has often been used as a proxy for population size, the relationship between diapausing egg bank size and genetic diversity has not been explicitly tested in zooplankton. We estimated the density and size of diapausing egg banks, habitat size and genetic diversity (for mitochondrial and nuclear markers) of 14 populations of the rotifer Brachionus plicatilis in an endorheic basin in the SE Iberian Peninsula. The size of B. plicatilis diapausing egg banks ranged across eight orders of magnitude (from 257 to 4.9 × 1010 eggs). Despite the small geographical scale, p…
Characterization of MHD convection in thin cell electrodeposition
2009
International audience; We are studying the effect of a magnetic field normal to the cell in electrodeposition of zinc arborescences. When the cell thickness is reduced, the MHD convection, responsible for morphology changes, spiraling, etc. is suppressed, but in a high magnetic field there is still an effect maybe due to small-scale hydrodynamic convection or to the Lorentz force on the growing metallic branches, the "Laplace" force.
Spotlight on the Survival Processing Advantage': An FNIRS Study on Adaptive Memory
2015
International audience; In the present study, participants had to rate words for their relevance in an ancestral survival scenario (e.g., is bottle relevant in the fictious scenario of being stranded in the grasslands of a foreign land without basic supplies) and for their pleasantness (e.g., is bottle a pleasant word?). A distractor task lasting a few minutes followed and the participants were then tested on their recall of the words. We used fNIRS to bilaterally monitor the dorsolateral-prefrontal cortex (DLPFC, known to be involved in strategic encoding) during the processing of verbal material in these two deep encoding situations. At the behavioral level, we replicated the survival pro…
Erosion of biodiversity affects the stability of soil microbial communities
2012
Anthropogenic activities have led to a significant modification/reduction of biodiversity. By observing this erosion, the understanding of the relationship between biodiversity and ecosystem functioning has emerged as a central issue in ecological and environmental sciences during the last decade. This relationship between diversity-stability-function has been extensively studied by plant ecologists, but remains largely unexplored for soil microorganisms. In this context, we studied the impact of an erosion of biodiversity on the stability of soil microbial communities (i.e. resistance and resilience) in response to two perturbations: a residual metallic stress (mercury input at 20 ppm) and…
Biodiversity and characterization of arbuscular mycorrhizal fungi at the molecular level
1994
Biodiversity within a biological group provides the basis for distinguishing members into genera and species according to taxonomic criteria, and between individuals within a species depending on more detailed differences at the genetic level. Diversity between species occurs after a genetic barrier has been created either by a geographic or genetic impedance of gene flow. Divergence can continue by nucleotide substitutions and by mutations in a broader sense (deletions, translocations, duplications), and resulting diversity can be evaluated at the molecular level and used as a phylogenetic character. Diversity at the subspecies level is a function of both mutation rates and gene flow betwe…
Loss in microbial diversity affects nitrogen cycling in soil
2013
International audience; Microbial communities have a central role in ecosystem processes by driving the Earth's biogeochemical cycles. However, the importance of microbial diversity for ecosystem functioning is still debated. Here, we experimentally manipulated the soil microbial community using a dilution approach to analyze the functional consequences of diversity loss. A trait-centered approach was embraced using the denitrifiers as model guild due to their role in nitrogen cycling, a major ecosystem service. How various diversity metrics related to richness, eveness and phylogenetic diversity of the soil denitrifier community were affected by the removal experiment was assessed by 454 s…