497 research outputs found
Heat Treatment Improvement of Dairy Products via Ohmic Heating Processes : Thermal and Hyrodynamic Effect on Fouling
Fouling and consequently cleaning of heat exchangers in the dairy industry are nowadays a significant issue still not solved for the processing of quite a large variety of products. Ohmic heating processes for food products a priori are well known to minimize the fouling phenomenon due to a totally different way of heating food by admitting the current directly in the product. Such a technology could be a good alternative to counter both fouling and cleaning aspects when pasteurizing or sterilizing dairy desserts known to generate large amounts of soil on heated surfaces. The aim of this experimental study was to investigate the respective roles of both the hydrodynamic parameters and surface electrode temperatures on the fouling phenomenon when heating a simple dairy mix designed to mimic dairy product behaviors
Ecology, behaviour and management of the European catfish
The extreme body sizes of âmegafishesâ associated with their high commercial values and recreational interests have made them highly threatened in their native range worldwide by human-induced impacts such as overexploitation. Meanwhile, and because of the aforementioned interests, some megafishes have been introduced outside of their native range. A notable exampled is the European catfish (Silurus glanis), one of the few siluriforms native from western Europe and among the 10 largest freshwater fish worldwide, attaining a total length over 2.7 m and a documented mass of 130 kg. Its distinct phylogeny and extreme size imply many features rare among other European fish such as peculiar behaviours (massive aggregations, beaching), consumption of large bodied prey, fast growth rate, long lifespan, high fecundity, nest guarding and large eggs. The spread of the species is likely to continue due to illegal introduction coupled with natural range extension due to current and future climate change. Based on these attributes and potential future risks, this introduced giant predator in European fresh waters could provide a novel model species of high utility for testing aspects of ecological and invasion theory and associated hypotheses. Here, we reviewed the most recent knowledge on the current distribution and the ecology of the species to understand how this can help advance our understanding of biological invasions. We also identified key research questions that should help stimulating new research on this intriguing, yet largely unknown, species and, more generally, on the ecology of invasive species
Seasonality, intensity, and duration of rainfall extremes change in a warmer climate
Precipitation extremes are expected to intensify under climate change with consequent impacts in flooding and ecosystem functioning. Here we use station data and highâresolution simulations from the WRF convection permitting climate model (âź4 km, 1 h) over the US to assess future changes in hourly precipitation extremes. It is demonstrated that hourly precipitation extremes and storm depths are expected to intensify under climate change and what is now a 20âyear rainfall will become a 7âyear rainfall on average for âź 75% of gridpoints over the US. This intensification is mostly expressed as an increase in rainfall tail heaviness. Statistically significant changes in the seasonality and duration of rainfall extremes are also exhibited over âź 95% of the domain. Our results suggest more nonâlinear future precipitation extremes with shorter spell duration that are distributed more uniformly throughout the year
Expression and trans-specific polymorphism of self-incompatibility RNases in Coffea (Rubiaceae)
Self-incompatibility (SI) is widespread in the angiosperms, but identifying the biochemical components of SI mechanisms has proven to be difficult in most lineages. Coffea (coffee; Rubiaceae) is a genus of old-world tropical understory trees in which the vast majority of diploid species utilize a mechanism of gametophytic self-incompatibility (GSI). The S-RNase GSI system was one of the first SI mechanisms to be biochemically characterized, and likely represents the ancestral Eudicot condition as evidenced by its functional characterization in both asterid (Solanaceae, Plantaginaceae) and rosid (Rosaceae) lineages. The S-RNase GSI mechanism employs the activity of class III RNase T2 proteins to terminate the growth of "self" pollen tubes. Here, we investigate the mechanism of Coffea GSI and specifically examine the potential for homology to S-RNase GSI by sequencing class III RNase T2 genes in populations of 14 African and Madagascan Coffea species and the closely related self-compatible species Psilanthus ebracteolatus. Phylogenetic analyses of these sequences aligned to a diverse sample of plant RNase T2 genes show that the Coffea genome contains at least three class III RNase T2 genes. Patterns of tissue-specific gene expression identify one of these RNase T2 genes as the putative Coffea S-RNase gene. We show that populations of SI Coffea are remarkably polymorphic for putative S-RNase alleles, and exhibit a persistent pattern of trans-specific polymorphism characteristic of all S-RNase genes previously isolated from GSI Eudicot lineages. We thus conclude that Coffea GSI is most likely homologous to the classic Eudicot S-RNase system, which was retained since the divergence of the Rubiaceae lineage from an ancient SI Eudicot ancestor, nearly 90 million years ago.United States National Science Foundation [0849186]; Society of Systematic Biologists; American Society of Plant Taxonomists; Duke University Graduate Schoolinfo:eu-repo/semantics/publishedVersio
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