8,562 research outputs found
Potential food production from forage legume-based-systems in Europe: an overview
peer-reviewedIntensification of EU livestock farming systems has been accompanied by the development of maize silage and intensively fertilised grasses at the expense of forage
legume crops. However in the new context of agriculture, the development of forage
legumes constitutes one of the pillars for future livestock farming systems with high
environmental and economical performances. Yield benefits of grass-clover mixtures
are equivalent fertiliser N inputs of 150 to 350 kg/ha, and productive grass-clover
mixtures can fix 100 to 380 kg N per hectare symbiotically from the atmosphere.
Animal intake of legumes is high and the rate of decline of legume nutritional
quality with advancing maturity is less than for grasses, especially in the case of
white clover, which makes mixed pastures easier to manage. Animal performances
at grazing are identical or higher on clover-enriched pastures. Due to their high
protein concentration, conserved forage legumes fit well with maize silage. Forage
legumes increase the concentration of beneficial α-linolenic acid in ruminant products.
Environmental balance of forage legumes is positive. Increasing the proportion
of white clover at the expense of mineral N fertilisation can reduce the risk of
nitrate leaching. Because forage legumes only require solar energy to fix N from the
air, they also reduce energy consumption and associated impacts. They contribute
to reduce the global warming potential of livestock systems by reducing emission
of enteric methane and nitrous oxide from pasture and crop production. As an
element of arable crop rotations, grass-clover leys suppress pests, diseases and
weeds, improve soil structure and prevent soil erosion and nitrate leaching.
Nevertheless, forage legumes have some limitations: expensive to harvest, difficulties of conservation, management of the associations. To take full advantage of forage legumes in the future, new research and development are required as well as financial support from the EU
Including virtual photons in strong interactions
In the perturbative field-theoretical models we investigate the inclusion of
the electromagnetic interactions into the purely strong theory that describes
hadronic processes. In particular, we study the convention for splitting
electromagnetic and strong interactions and the ambiguity of such a splitting.
The issue of the interpretation of the parameters of the low-energy effective
field theory in the presence of electromagnetic interactions is addressed, as
well as the scale and gauge dependence of the effective theory couplings. We
hope, that the results of these studies are relevant for the electromagnetic
sector of ChPT.Comment: Talk presented at the International conference on Quarks and Nuclear
Physics, June 9-14, 2002, Juelich, German
On the Connectivity of Unions of Random Graphs
Graph-theoretic tools and techniques have seen wide use in the multi-agent
systems literature, and the unpredictable nature of some multi-agent
communications has been successfully modeled using random communication graphs.
Across both network control and network optimization, a common assumption is
that the union of agents' communication graphs is connected across any finite
interval of some prescribed length, and some convergence results explicitly
depend upon this length. Despite the prevalence of this assumption and the
prevalence of random graphs in studying multi-agent systems, to the best of our
knowledge, there has not been a study dedicated to determining how many random
graphs must be in a union before it is connected. To address this point, this
paper solves two related problems. The first bounds the number of random graphs
required in a union before its expected algebraic connectivity exceeds the
minimum needed for connectedness. The second bounds the probability that a
union of random graphs is connected. The random graph model used is the
Erd\H{o}s-R\'enyi model, and, in solving these problems, we also bound the
expectation and variance of the algebraic connectivity of unions of such
graphs. Numerical results for several use cases are given to supplement the
theoretical developments made.Comment: 16 pages, 3 tables; accepted to 2017 IEEE Conference on Decision and
Control (CDC
Optical Stark Effect and Dressed Excitonic States in a Mn-doped Quantum Dot
We report on the observation of spin dependent optically dressed states and
optical Stark effect on an individual Mn spin in a semiconductor quantum dot.
The vacuum-to-exciton or the exciton-to-biexciton transitions in a Mn-doped
quantum dot are optically dressed by a strong laser field and the resulting
spectral signature is measured in photoluminescence. We demonstrate that the
energy of any spin state of a Mn atom can be independently tuned using the
optical Stark effect induced by a control laser. High resolution spectroscopy
reveals a power, polarization and detuning dependent Autler-Townes splitting of
each optical transition of the Mn-doped quantum dot. This experiment
demonstrates a complete optical resonant control of the exciton-Mn system
Female Genital Warts: Global Trends and Treatments
The increasing incidence of human papillomavirus (HPV) infection and HPV-associated conditions such as genital warts in women is a global concern. Genital warts are a clinical manifestation of HPV types 6 and 11, and are estimated to affect 1% of sexually active adults aged between 15 and 49. HPV infection is also strongly associated with cervical cancer, and is prevalent in as many as 99% of cases. The psychological stress of having genital warts is often greater than the morbidity of the disease, and therefore successful treatment is crucial. Current treatments are patient-applied and provider-administered therapies. Imiquimod 5% cream, a patient-applied therapy, is an efficacious treatment with tolerable side-effects and a low recurrence rate, and has the potential to be an effective strategy for the management of genital warts
Mechanism of fragmentation and atomization of molecular ions in gasdynamic transport cell
The fragmentation of molecular ions formed upon the electrospraying of a sample and transported through the gasdynamic system of a mass spectrometer equipped with an IESAP (Ion Extraction from Solution at Atmospheric Pressure) source has been experimentally studied. It is established that ion fragmentation in a Kantorowicz-Gray type cell takes place in the immediate vicinity of a skimmer port, apparently, as a result of collisions between ions (accelerated in an electric field) and stagnant gas. Molecular mechanisms of fragmentation are considered and it is concluded that this process can take place in a single ion-molecule collision even
Are aerobic fitness and repeated sprint ability linked to fatigue in professional soccer match-play? A pilot study
This investigation examined the association between aerobic fitness and repeated sprint ability and match-related fatigue in 9 professional outfield soccer players. Aerobic fitness using maximal aerobic speed (MAS) was determined via a continuous progressive incremental running test conducted on a motorised treadmill. A repeated sprint ability test (6 successive 6 s sprints separated by 20 s passive recovery) was performed on a non-motorised treadmill to determine mean and best sprint times and a percentage decrement score (%PD). A total of 114 observations of physical performance derived using computerised time motion analyses were collected from 33 matches. Correlations between fitness test and match-play measures were examined for 1) accumulated fatigue: percentage difference between halves for total distance covered per minute, distance run at high-intensities (HIR, actions for 1s duration, >19.1 km/h) per minute, mean recovery time between high-intensity runs, and percentage difference between the distance covered in HIR in the first 5- and 15-minute periods versus the final 5- and 15-minute periods respectively in normal time; and for 2) transient fatigue: percentage difference between the distance covered in HIR in a peak 5-minute period and the subsequent 5-minute period and for the latter compared to the mean for all other 5-minute periods. No significant relationships were observed between MAS and fatigue scores (magnitude of associations: trivial to large). For mean and best sprint times and %PD, the only reported significant correlation (r=0.77, magnitude of association: very large, p<0.05) was between %PD and the % difference across halves for mean recovery time between high-intensity runs (magnitude of other associations: small to large). Criterion measures from tests of aerobic fitness and repeated sprint ability might not accurately depict a player’s capacity to resist fatigue during professional soccer competition
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