1,650 research outputs found
Charge Fractionalization on Quantum Hall Edges
We discuss the propagation and fractionalization of localized charges on the
edges of quantum Hall bars of variable widths, where interactions between the
edges give rise to Luttinger liquid behavior with a non-trivial interaction
parameter g. We focus in particular on the separation of an initial charge
pulse into a sharply defined front charge and a broader tail. The front pulse
describes an adiabatically dressed electron which carries a non-integer charge,
which is \sqrt{g} times the electron charge. We discuss how the presence of
this fractional charge can, in principle, be detected through measurements of
the noise in the current created by tunneling of electrons into the system. The
results are illustrated by numerical simulations of a simplified model of the
Hall bar.Comment: 15 page
Impact of coccidial infection on vaccine- and vvIBDV in lymphoid tissues of SPF chickens as detected by RT-PCR
BACKGROUND: This study aimed at investigating a potential effect caused by coccidia on the immune response to vaccine- and very virulent infectious bursal disase virus (vvIBDV) in SPF chickens. METHODS: Two groups of three weeks old SPF chickens were vaccinated prior to inoculation with coccidia and challenge with virulent IBDV, all within a period of eight days. Two control groups were similarly treated, except that challenge with field virus was omitted in one group while inoculation with coccidia was omitted in the other group. Clinical signs, lesions in the intestines caused by coccidia, lesions in the bursa of Fabricius caused by IBDV, IBDV-antibody titres, and virus detection by reverse transcription polymerase chain reaction (RT-PCR) were compared among the groups. Lymphoid tissues and swab samples were analysed by general RT-PCR, and positive results were identified by strain specific duplex (DPX) RT-PCR. RESULTS: In the tripple-infected groups, vaccine strain IBDV was detected in spleen and thymus tissues, and no field virus was detected in bursa samples, contrary to the double-infected groups. CONCLUSION: The results suggest an enhancing effect on the immune response caused by subclinical coccidiosis and vvIBDV acting in concert
Fabrication of a scaled MgB2 racetrack demonstrator pole for a 10 MW direct drive wind turbine generator
Field windings made of MgB2 wires or tapes are considered for their potential to reduce volume, weight and cost of large offshore wind turbine generators. To gain experience of how to use this relatively new material in full-scale generators, tests of different winding methodologies and techniques are needed. In this paper, we describe in detail the steps used to wind a racetrack coil with a length of 1 m and a width of 0.5 m out of 4.5 km of MgB2 superconducting tape. The width corresponds to a full-scale pole of a 10 MW generator, whereas the length of the straight section is shorter than the corresponding full-scale pole. The coil was built up of 10 double pancake coils. Each double pancake coil was wet-wound using a semi-automatic winding process, where Stycast 2850 was applied directly to the MgB2 tape without any other dedicated electrical insulation. The strengths and weaknesses of the winding process are discussed and compared to the dry-winding method.acceptedVersio
Fabrication of a scaled MgB2 racetrack demonstrator pole for a 10 MW direct drive wind turbine generator
Field windings made of MgB2 wires or tapes are considered for their potential to reduce volume, weight and cost of large offshore wind turbine generators. To gain experience of how to use this relatively new material in full-scale generators, tests of different winding methodologies and techniques are needed. In this paper, we describe in detail the steps used to wind a racetrack coil with a length of 1 m and a width of 0.5 m out of 4.5 km of MgB2 superconducting tape. The width corresponds to a full-scale pole of a 10 MW generator, whereas the length of the straight section is shorter than the corresponding full-scale pole. The coil was built up of 10 double pancake coils. Each double pancake coil was wet-wound using a semi-automatic winding process, where Stycast 2850 was applied directly to the MgB2 tape without any other dedicated electrical insulation. The strengths and weaknesses of the winding process are discussed and compared to the dry-winding method.acceptedVersio
The Fulling-Unruh effect in general stationary accelerated frames
We study the generalized Unruh effect for accelerated reference frames that
include rotation in addition to acceleration. We focus particularly on the case
where the motion is planar, with presence of a static limit in addition to the
event horizon. Possible definitions of an accelerated vacuum state are examined
and the interpretation of the Minkowski vacuum state as a thermodynamic state
is discussed. Such athermodynamic state is shown to depend on two parameters,
the acceleration temperature and a drift velocity, which are determined by the
acceleration and angular velocity of the accelerated frame. We relate the
properties of Minkowski vacuum in the accelerated frame to the excitation
spectrum of a detector that is stationary in this frame. The detector can be
excited both by absorbing positive energy quanta in the "hot" vacuum state and
by emitting negative energy quanta into the "ergosphere" between the horizon
and the static limit. The effects are related to similar effects in the
gravitational field of a rotating black hole.Comment: Latex, 39 pages, 5 figure
Evaluating the capacity of human gut microorganisms to colonize the zebrafish larvae (Danio rerio)
Indexación: Scopus.In this study we evaluated if zebrafish larvae can be colonized by human gut microorganisms. We tested two strategies: (1) through transplantation of a human fecal microbiota and (2) by successively transplanting aerotolerant anaerobic microorganisms, similar to the colonization in the human intestine during early life. We used conventionally raised zebrafish larvae harboring their own aerobic microbiota to improve the colonization of anaerobic microorganisms. The results showed with the fecal transplant, that some members of the human gut microbiota were transferred to larvae. Bacillus, Roseburia, Prevotella, Oscillospira, one unclassified genus of the family Ruminococcaceae and Enterobacteriaceae were detected in 3 days post fertilization (dpf) larvae; however only Bacillus persisted to 7 dpf. Successive inoculation of Lactobacillus, Bifidobacterium and Clostridioides did not improve their colonization, compared to individual inoculation of each bacterial species. Interestingly, the sporulating bacteria Bacillus clausii and Clostridioides difficile were the most persistent microorganisms. Their endospores persisted at least 5 days after inoculating 3 dpf larvae. However, when 5 dpf larvae were inoculated, the proportion of vegetative cells in larvae increased, revealing proliferation of the inoculated bacteria and better colonization of the host. In conclusion, these results suggest that it is feasible to colonize zebrafish larvae with some human bacteria, such as C. difficile and Bacillus and open an interesting area to study interactions between these microorganisms and the host. © 2018 Valenzuela, Caruffo, Herrera, Medina, Coronado, Feijóo, Muñoz, Garrido, Troncoso, Figueroa, Toro, Reyes-Jara, Magne and Navarrete.https://www.frontiersin.org/articles/10.3389/fmicb.2018.01032/ful
Q-band Point to Multipoint Backhaul Deployment: the SARABAND Case Study
This paper describes the small scale field trial
deployed within the SARABAND project to provide final
network performances comparable to fibre optics in a costeffective
manner for the 4G small cell backhaul. The
performances of the system have been measured, obtaining over
100 Mbps peak capacity and frame error rates compliant with
operators’ requirements.The European Commission is gratefully acknowledged for funding the ICT-2011-288267 SARABAND project in the 7th Framework Programme and the H2020-644678 TWEETHER project.Vilar Mateo, R.; Martà Sendra, J.; RamÃrez, A.; Bou, J.; Magne, F. (2015). Q-band Point to Multipoint Backhaul Deployment: the SARABAND Case Study. En 2015 European Conference on Networks and Communications (EuCNC). Institute of Electrical and Electronics Engineers (IEEE). 788-789. http://hdl.handle.net/10251/62273S78878
Constraining the Two-Higgs-Doublet-Model parameter space
We confront the Two-Higgs-Doublet Model with a variety of experimental
constraints as well as theoretical consistency conditions. The most
constraining data are the \bar B\to X_s\gamma decay rate (at low values of
M_{H^\pm}), and \Delta\rho (at both low and high M_{H^\pm}). We also take into
account the B\bar B oscillation rate and R_b, or the width \Gamma(Z\to b\bar b)
(both of which restrict the model at low values of \tan\beta), and the
B^-\to\tau\nu_\tau decay rate, which restricts the model at high \tan\beta and
low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs
boson is considered, as well as the muon anomalous magnetic moment. Since
perturbative unitarity excludes high values of \tan\beta, the model turns out
to be very constrained. We outline the remaining allowed regions in the
\tan\beta-M_{H^\pm} plane for different values of the masses of the two
lightest neutral Higgs bosons, and describe some of their properties.Comment: 17 pages, 17 figure
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