5,074 research outputs found
FERMIONIC ZERO MODES FOR DYONS AND CHIRAL SYMMETRY BREAKING IN QCD
Dyonic classical solutions of Yang-Mills theory are considered and the
complete set of fermionic zero modes of these solutions are studied.
Representing the QCD vacuum as a gas of dyons, one obtains chiral symmetry
breaking due to zero modes similarly to the case of instantonic vacuum.Comment: 23 pages, no figures, PostScrip
Lepton Number Violation from Colored States at the LHC
The possibility to search for lepton number violating signals at the Large
Hadron Collider (LHC) in the colored seesaw scenario is investigated. In this
context the fields that generate neutrino masses at the one-loop level are
scalar and Majorana fermionic color-octets of SU(3). Due to the QCD strong
interaction these states may be produced at the LHC with a favorable rate. We
study the production mechanisms and decays relevant to search for lepton number
violation signals in the channels with same-sign dileptons. In the simplest
case when the two fermionic color-octets are degenerate in mass, one could use
their decays to distinguish between the neutrino spectra. We find that for
fermionic octets with mass up to about 1 TeV the number of same-sign dilepton
events is larger than the standard model background indicating a promising
signal for new physics.Comment: minor corrections, added reference
Non-renormalization of next-to-extremal correlators in N=4 SYM and the AdS/CFT correspondence
We show that next-to-extremal correlators of chiral primary operators in N=4
SYM theory do not receive quantum corrections to first order in perturbation
theory. Furthermore we consider next-to-extremal correlators within AdS
supergravity. Here the exchange diagrams contributing to these correlators
yield results of the same free-field form as obtained within field theory. This
suggests that quantum corrections vanish at strong coupling as well.Comment: 21 pages, LaTex, 9 eps figures, typos corrected and references adde
Electrical compatibility of transmission fluids in electric vehicles
The in electrical vehicles, where the electric motor is inside the transmissielectrical compatibility of the automatic transmission fluids (ATFs) is very important on and in contact with the ATF. This work studies the influence of factors like temperature, time, and air exposition on the oxidation of three ATFs and their changes in electrical conductivity. The results showed that the higher content of additive the lower variations of electrical conductivity with the oxidation; the measurements of electrical conductivity are better than FT-IR ones for monitoring oil thermo-oxidative degradation at initial periods; the conventional ATFs could maintain good electrical compatibility in electrified drivelines, although their materials compatibility and copper corrosion protection of electrical components should be also tested
A dark energy multiverse
We present cosmic solutions corresponding to universes filled with dark and
phantom energy, all having a negative cosmological constant. All such solutions
contain infinite singularities, successively and equally distributed along
time, which can be either big bang/crunchs or big rips singularities.
Classicaly these solutions can be regarded as associated with multiverse
scenarios, being those corresponding to phantom energy that may describe the
current accelerating universe
Effect of early cryoprecipitate transfusion versus standard care in women who develop severe postpartum haemorrhage (ACROBAT) in the UK: a protocol for a pilot cluster randomisedtrial
Introduction The incidence of severe postpartum haemorrhage (PPH) that requires blood transfusion is on the increase. Fibrinogen levels have been shown to drop early and significantly during PPH, which is associated with worse outcomes. Early fibrinogen replacement could potentially improve outcomes. No studies have investigated the clinical impact of early cryoprecipitate transfusion in PPH. Prior to performing a full-scale trial, a pilot study is needed to determine feasibility of the intervention and recruitment.
Methods ACROBAT is a cluster-randomised pilot study with a qualitative evaluation. Four large London maternity units are randomised to either the intervention or control group. The intervention group will adapt their major obstetric haemorrhage procedures to administer cryoprecipitate early for primary PPH. The control group will retain their standard of care.
We include women at >24 weeks gestation who are actively bleeding within 24âhours of delivery and for whom transfusion of red blood cells (RBCs) has been started. We exclude women who decline blood transfusions in advance or have inherited Factor XIII or fibrinogen deficiency. Due to the emergency nature of the intervention, informed consent for administering the intervention is waived.
The primary objective is to assess the feasibility of administering cryoprecipitate within 90âmin of RBC request, as compared with standard treatment where cryoprecipitate is given later or not at all. Secondary objectives include the feasibility of recruitment and data collection, reasons for and barriers to consent, preliminary maternal clinical outcomes, identification of the optimal infrastructure pathways for study delivery, and acceptability of the intervention and outcomes
Response of alluvial systems to Late Pleistocene climate changes recorded by environmental magnetism in the Añavieja Basin (Iberian Range, NE Spain)
Environmental magnetic proxies were analyzed in a relatively monotonous, ~25.3m thick alluvial sedimentary sequence drilled in the Añavieja Basin (NE Spain). Results from the core AĂ2 suggest that the concentrationdependent magnetic parameters mainly reflect variations in the content of detrital magnetite, sourced in the catchment rocks and soils of the basin, via changes in the dynamics of alluvial fans due to temperature changes in the northern hemisphere during the Late Pleistocene. The correspondence between the magnetic proxies and the temperature variations in the North Atlantic region (NGRIP curve) indicates that higher (lower) concentrations and finer (coarser) magnetite grains coincide with warm (cold) periods. We propose that during cold periods, a sparser vegetation cover favored the incoming of higher energy runoff bearing coarser sediments to the basin that are relatively impoverished in magnetite. In contrast, during warm periods, the wider distribution of the vegetation cover associated with the lower runoff energy lead to finer, magnetite-richer sediment input to the basin. Maghemite, presumably of pedogenic origin, appears to be present also in the studied alluvial sediments. Further studies are necessary to unravel its palaeoclimatic significance
Global monitoring of soil multifunctionality in drylands using satellite imagery and field data
Models derived from satellite image data are needed to monitor the status of terrestrial ecosystems across large spatial scales. However, a remote sensing-based approach to quantify soil multifunctionality at the global scale is missing despite significant research efforts on this topic. A major constraint for doing so is the availability of suitable global-scale field data to calibrate remote sensing indicators (RSI) and, to a lesser extent, the sensitivity of spectral data of available satellite sensors to soil background and atmospheric conditions. Here, we aimed to develop a soil multifunctionality model to monitor global drylands coupling ground data on 14 soil functions of 222 dryland areas from six continents to 18 RSI derived from a time series (2006â2013) Landsat dataset. Among the RSI evaluated, the chlorophyll absorption ratio index was the best predictor of soil multifunctionality in single-variable-based models (râ=â0.66, Pâ<â0.01, NMRSEâ=â0.17). However, a multi-variable RSI model combining the chlorophyll absorption ratio index, the global environment monitoring index and the canopy-air temperature difference improved the accuracy of quantifying soil multifunctionality (râ=â0.73, Pâ<â0.01, NMRSEâ=â0.15). Furthermore, the correlation between RSI and soil variables shows a wide range of accuracy with upper and lower values obtained for AMI (râ=â0.889, NMRSEâ=â0.05) and BGL (râ=â0.685, NMRSEâ=â0.18) respectively. Our results provide new insights on assessing soil multifunctionality using RSI that may help to monitor temporal changes in the functioning of global drylands effectively.Field data were obtained with the support of the European Research Council (ERC) grant agreement 242658 (BIOCOM). HernĂĄndez-Clemente R was supported by the RamĂłn y Cajal program (RYC2020-029187-I) and the State Plan for Scientific and Subprogram for Knowledge Generation (PID2021-124058OA-I00) from the Spanish Ministry of Science and Innovation (RYC2020-029187-I). Maestre FT acknowledges support from Generalitat Valenciana (CIDEGENT/2018/041) and the Spanish Ministry of Science and Innovation (EUR2022-134048)
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