67 research outputs found
Coherent Control of Quantum Dynamics with Sequences of Unitary Phase-Kick Pulses
Coherent optical control schemes exploit the coherence of laser pulses to
change the phases of interfering dynamical pathways in order to manipulate
dynamical processes. These active control methods are closely related to
dynamical decoupling techniques, popularized in the field of Quantum
Information. Inspired by Nuclear Magnetic Resonance (NMR) spectroscopy,
dynamical decoupling methods apply sequences of unitary operations to modify
the interference phenomena responsible for the system dynamics thus also
belonging to the general class of coherent control techniques. Here we review
related developments in the fields of coherent optical control and dynamical
decoupling, with emphasis on control of tunneling and decoherence in general
model systems. Considering recent experimental breakthroughs in the
demonstration of active control of a variety of systems, we anticipate that the
reviewed coherent control scenarios and dynamical decoupling methods should
raise significant experimental interest.Comment: 52 pages, 7 figure
Carnivore Translocations and Conservation: Insights from Population Models and Field Data for Fishers (Martes pennanti)
Translocations are frequently used to restore extirpated carnivore populations. Understanding the factors that influence translocation success is important because carnivore translocations can be time consuming, expensive, and controversial. Using population viability software, we modeled reintroductions of the fisher, a candidate for endangered or threatened status in the Pacific states of the US. Our model predicts that the most important factor influencing successful re-establishment of a fisher population is the number of adult females reintroduced (provided some males are also released). Data from 38 translocations of fishers in North America, including 30 reintroductions, 5 augmentations and 3 introductions, show that the number of females released was, indeed, a good predictor of success but that the number of males released, geographic region and proximity of the source population to the release site were also important predictors. The contradiction between model and data regarding males may relate to the assumption in the model that all males are equally good breeders. We hypothesize that many males may need to be released to insure a sufficient number of good breeders are included, probably large males. Seventy-seven percent of reintroductions with known outcomes (success or failure) succeeded; all 5 augmentations succeeded; but none of the 3 introductions succeeded. Reintroductions were instrumental in reestablishing fisher populations within their historical range and expanding the range from its most-contracted state (43% of the historical range) to its current state (68% of the historical range). To increase the likelihood of translocation success, we recommend that managers: 1) release as many fishers as possible, 2) release more females than males (55–60% females) when possible, 3) release as many adults as possible, especially large males, 4) release fishers from a nearby source population, 5) conduct a formal feasibility assessment, and 6) develop a comprehensive implementation plan that includes an active monitoring program
Cork oak vulnerability to fire: the role of bark harvesting, tree characteristics and abiotic factors
Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to
disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper
we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire
tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European
countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire
tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and
ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are
major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently
debarked individuals) and decreased with increasing bark thickness until cork was 3–4 cm thick. This bark thickness
corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire
during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark
thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees
burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help
estimating the impact of fire and to support management decisions. The results suggested that an appropriate
management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or
increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak
ecosystemsinfo:eu-repo/semantics/publishedVersio
CaracterÃsticas da reação tipo 1 e associação com vÃrus B e C da hepatite na hansenÃase
Year in review in Intensive Care Medicine 2009: II. Neurology, cardiovascular, experimental, pharmacology and sedation, communication and teaching
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Examination of the effects of nitrogen on the CVD diamond growth mechanism using <i>in-situ</i> molecular beam mass spectrometry
Gas-phase composition measurements during chlorine assisted chemical vapor deposition of diamond: A molecular beam mass spectrometric study
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