Search results for "reservoir"
showing 10 items of 216 documents
The use of zooplankton metrics to determine the trophic status and ecological potential: An approach in a large Mediterranean watershed.
2021
In the European Water Framework Directive, zooplankton was not included as a Biological Quality Element despite its important place in the aquatic trophic web. In the present study on zooplankton abundances and biomasses, we used several metrics to test their ability to detect differences among trophic statuses and ecological potential levels, and collected a large sum of data in more than 60 reservoirs at Ebro watershed, on more than 300 sampling occasions over 10 years. Our results indicate that most zooplankton metrics are correlated to environmental variables that determine reservoirs’ trophic states, especially chlorophyll a and total phosphorus. The metrics with better sensitivity to …
Phytoplankton equilibrium phases during thermal stratification in a deep subtropical reservoir
2008
SUMMARY 1. Equilibrium and non-equilibrium hypotheses have often been used to explain observations in community ecology. Published case studies have demonstrated that steady state phytoplankton assemblages are more likely to occur in deep lakes than in shallow mixed ones. 2. Phytoplankton seasonal succession was studied by weekly sampling in Faxinal Reservoir (S Brazil), a subtropical deep, clear, warm monomictic and slightly eutrophic reservoir. This study demonstrated an alternation of steady and non-steady state phases of phytoplankton assemblages with different dominant species during the steady states. 3. During the studied period, three steady states were identified with different dom…
The promise of spintronics for unconventional computing
2021
Novel computational paradigms may provide the blueprint to help solving the time and energy limitations that we face with our modern computers, and provide solutions to complex problems more efficiently (with reduced time, power consumption and/or less device footprint) than is currently possible with standard approaches. Spintronics offers a promising basis for the development of efficient devices and unconventional operations for at least three main reasons: (i) the low-power requirements of spin-based devices, i.e., requiring no standby power for operation and the possibility to write information with small dynamic energy dissipation, (ii) the strong nonlinearity, time nonlocality, and/o…
Asymptotic entanglement of two atoms in a squeezed light field
2011
The dynamics of entanglement between two - level atoms interacting with a common squeezed reservoir is investigated. It is shown that for spatially separated atoms there is a unique asymptotic state depending on the distance between the atoms and the atom - photons detuning. In the regime of strong correlations there is a one - parameter family of asymptotic steady - states depending on initial conditions. In contrast to the thermal reservoir both types of asymptotic states can be entangled. We calculate the amount of entanglement in the system in terms of concurrence.
Nanoscale Heat Engine Beyond the Carnot Limit
2013
We consider a quantum Otto cycle for a time-dependent harmonic oscillator coupled to a squeezed thermal reservoir. We show that the efficiency at maximum power increases with the degree of squeezing, surpassing the standard Carnot limit and approaching unity exponentially for large squeezing parameters. We further propose an experimental scheme to implement such a model system by using a single trapped ion in a linear Paul trap with special geometry. Our analytical investigations are supported by Monte Carlo simulations that demonstrate the feasibility of our proposal. For realistic trap parameters, an increase of the efficiency at maximum power of up to a factor of 4 is reached, largely ex…
Structure and Sensory Analyses of Tainting Substances in Finnish Freshwater Environments
1988
GC/MS/SNIFF/TASTE methods have been used in Finland to identify the causes of three tainting problems in water and one in fish nets. Structure determination was often verified by comparison with authentic compounds. Algal growth was implicated to be the source of geosmin and MIB in river water in Northern Finland and was associated with the appearance of tainting problems in raw water and reservoir water in Åland county. Terpenoids (e.g. camphor), degradation products of natural lipids (e.g. aldehydes, ketones and unsaturated aliphatic compounds) and volatile organohalogen compounds were frequently found in contaminated water but showed minor tainting effects compared to geosmin and MIB. Di…
Human leptospirosis cases in Palermo Italy. The role of rodents and climate
2018
Many regions of the world are increasingly exposed to leptospirosis due to poverty, global warming and high urban density. Here, we report a molecular survey for pathogenic Leptospira spp. in rodents and two symptomatic human cases of leptospirosis in the city of Palermo, Italy.Four rodent species were captured in six areas of the city, and a molecular analysis for pathogenic Leptospira spp. on DNA from the kidney samples showed a different prevalence of leptospirosis in all the species of rodents. In addition, two human cases that occurred in May and October of 2009 in the city were also reported. A 67-year-old woman recovered after antibiotic treatment, whereas a 71-year-old woman did not…
Molecular detection of Anaplasma phagocytophilum DNA in the lesser horseshoe bat (Rhinolophus hipposideros) guano
2018
AbstractAlthough bats are increasingly recognised as potential reservoir hosts of human zoonotic pathogens, bacteria in bats are still poorly studied. To investigate the DNA faecal prevalence of the bacterium Anaplasma phagocytophilum, we sampled 23 lesser horseshoe bat (Rhinolophus hipposideros) maternity colonies located in buildings (churches, barns) in rural villages of eastern France. A total of 552 faecal samples were collected from 278 individuals. Anaplasma phagocytophilum DNA was detected in the faeces of 63 individuals (22.7%). Such high prevalence might suggest persistent infection in bats and/or a frequent consumption of insect preys carrying bacteria. Faecal DNA prevalence vari…
Key roles for freshwater A ctinobacteria revealed by deep metagenomic sequencing
2014
Freshwater ecosystems are critical but fragile environments directly affecting society and its welfare. However, our understanding of genuinely freshwater microbial communities, constrained by our capacity to manipulate its prokaryotic participants in axenic cultures, remains very rudimentary. Even the most abundant components, freshwater Actinobacteria, remain largely unknown. Here, applying deep metagenomic sequencing to the microbial community of a freshwater reservoir, we were able to circumvent this traditional bottleneck and reconstruct de novo seven distinct streamlined actinobacterial genomes. These genomes represent three new groups of photoheterotrophic, planktonic Actinobacteria.…
A multi-scenario Decision Support System for real-time operation of over-year multi-reservoir system 2. DSS simulation
2019
A companion paper (Arena et al, 2019) has introduced the architecture of the DSS and has described its governing equations. In a real-time, dynamic decision-making context, it is a tool to support decisions at the current time step concerning water allocations to municipal demand centres and irrigation districts as well as additional intakes from costly water sources in a water resources system featuring reservoirs with over-year behaviour. The DSS is designed as a linearized MIP (mixed integer programming) optimization model and as such, it includes an objective function and constraints on 1) mass balances at system’s nodes, 2) systems’ topology, 3) component’s capacity, 4) spills, as well…