Search results for "flu"
showing 10 items of 16583 documents
Changes of energy fluxes in marine animal forests of the anthropocene: Factors shaping the future seascape
2019
12 pages, 3 figures
Effect of Intensity and Mode of Artificial Upwelling on Particle Flux and Carbon Export
2021
Reduction of anthropogenic CO2 emissions alone will not sufficiently restrict global warming and enable the 1.5°C goal of the Paris agreement to be met. To effectively counteract climate change, measures to actively remove carbon dioxide from the atmosphere are required. Artificial upwelling has been proposed as one such carbon dioxide removal technique. By fueling primary productivity in the surface ocean with nutrient-rich deep water, it could potentially enhance downward fluxes of particulate organic carbon (POC) and carbon sequestration. In this study we investigated the effect of different intensities of artificial upwelling combined with two upwelling modes (recurring additions vs. on…
Ecosystem responses to increased organic carbon concentration: comparing results based on long-term monitoring and whole-lake experimentation
2019
Recent increases in terrestrial dissolved organic carbon (DOC) concentrations in northern inland waters have many ecological consequences. We examined available data on carbon cycles and food webs of 2 boreal headwater lakes in southern Finland. Basic limnology and catchment characteristics of a pristine lake, Valkea-Kotinen (VK), were monitored over the past 25 years while the lake has undergone browning and DOC increased from similar to 11 to 13 mg L-1. Pronounced changes in the early 2000s represent a regime shift in DOC concentration and color. Lake Alinen Mustajarvi (AM) was manipulated for 2 years by additions of labile DOC (cane sugar), raising the DOC concentration from similar to 1…
Étude paléobotanique d’une lentille argileuse cénomanienne de la carrière de Hucheloup, Maine-et-Loire, NO France : implications taxonomiques, strati…
2017
International audience; A Cenomanian clay lens in Hucheloup Quarry (Maine-et-Loire, north-western France) has yielded 82 foliar compressions and impressions, of which 62 were identified at several taxonomic levels. The plants are ascribed to diverse Pinales (27%), ferns (27%), Ginkgoales (26%), angiosperms (19%) and Cycadales (1%). The most abundant species in the assemblage are Frenelopsis alata (K. Feistmantel) E. Knobloch emend. J. Kvaček (Pinales) and Eretmophyllum obtusum (Velenovský) J. Kvaček (syn. E. andegavense Pons, Bourreau et Broutin) (Ginkgoales). Wood fragments, along with very well-preserved cuticles, have also been recovered and identified. The specimens are usually very fra…
Developmental aspects of morphological disparity dynamics: a simple analytical exploration
2011
15 pages; International audience; We devised a simple model for assessing the role of development in shaping the evolution of morphological disparity. Disparity of a clade at any given time is expressed in terms of the developmental dynamics that lead to the variety of adult morphotypes observed. We use assumed phenotypic manifestations of developmental processes, as they could be detected from allometric characterizations, to distinguish a few, nonexclusive types of evolutionary changes in ontogeny. On the basis of this formalization, we describe the diversification of hypothetical clades, using the standard curve of adult morphological disparity, the curve of juvenile disparity, and the c…
Functional assessment of morphological homoplasy in stem-gnathostomes
2021
Osteostraci and Galeaspida are stem-gnathostomes, occupying a key phylogenetic position for resolving the nature of the jawless ancestor from which jawed vertebrates evolved more than 400 million years ago. Both groups are characterized by the presence of rigid headshields that share a number of common morphological traits, in some cases hindering the resolution of their interrelationships and the exact nature of their affinities with jawed vertebrates. Here, we explore the morphological and functional diversity of osteostracan and galeaspid headshields using an innovative approach that combines geometric morphometrics and computational fluid dynamics, thereby constraining the underlying fa…
Hierarchy is Detrimental for Human Cooperation
2015
Studies of animal behavior consistently demonstrate that the social environment impacts cooperation, yet the effect of social dynamics has been largely excluded from studies of human cooperation. Here, we introduce a novel approach inspired by nonhuman primate research to address how social hierarchies impact human cooperation. Participants competed to earn hierarchy positions and then could cooperate with another individual in the hierarchy by investing in a common effort. Cooperation was achieved if the combined investments exceeded a threshold, and the higher ranked individual distributed the spoils unless control was contested by the partner. Compared to a condition lacking hierarchy, c…
Gametic and somatic embryogenesis through in vitro anther culture of different Citrus genotypes
2015
Abstract: In vitro tissue culture represents a useful technique for advancing Citrus breeding and propagation. Among in vitro regeneration systems, anther culture is commonly used to produce haploids and doubled haploids for a fast-track producing homozygous lines, in comparison with the traditional self-pollination approach, which involves several generations of selfing. In addition, anthers culture can produce somatic embryos that can also be used for clonal propagation. In this study, two thermal shocks were applied to the anthers of six Citrus genotypes (two clementine and four sweet oranges), just after they were put in culture. The response obtained was different depending on the geno…
Anhydrobiosis in yeasts: Glutathione synthesis by yeast Ogataea (Hansenula) polymorpha cells after their dehydration-rehydration.
2019
The possibility of using active dry microbial preparations in biotechnological processes is essential for the development of new modern industrial technologies. In this study, we show the possibility of obtaining such preparations of the genetically engineered yeast strain Ogataea (Hansenula) polymorpha with glutathione overproduction. Special pre-treatment involving the gradual rehydration of dry cells in water vapour led to the restoration/reactivation of almost 100% of dehydrated cells. Furthermore, dry cells do not lose their viability during storage at room temperatures. Application of dry cells as the inoculum provides the same levels of glutathione synthesis as that of a native yeast…
In vivo photoprotection mechanisms observed from leaf spectral absorbance changes showing VIS–NIR slow-induced conformational pigment bed changes
2019
Abstract Regulated heat dissipation under excessive light comprises a complexity of mechanisms, whereby the supramolecular light-harvesting pigment–protein complex (LHC) shifts state from light harvesting towards heat dissipation, quenching the excess of photo-induced excitation energy in a non-photochemical way. Based on whole-leaf spectroscopy measuring upward and downward spectral radiance fluxes, we studied spectrally contiguous (hyperspectral) transient time series of absorbance A(λ,t) and passively induced chlorophyll fluorescence F(λ,t) dynamics of intact leaves in the visible and near-infrared wavelengths (VIS–NIR, 400–800 nm) after sudden strong natural-like illumination exposure. …