17,221 research outputs found
Unitarity of the Leptonic Mixing Matrix
We determine the elements of the leptonic mixing matrix, without assuming
unitarity, combining data from neutrino oscillation experiments and weak
decays. To that end, we first develop a formalism for studying neutrino
oscillations in vacuum and matter when the leptonic mixing matrix is not
unitary. To be conservative, only three light neutrino species are considered,
whose propagation is generically affected by non-unitary effects. Precision
improvements within future facilities are discussed as well.Comment: Standard Model radiative corrections to the invisible Z width
included. Some numerical results modified at the percent level. Updated with
latest bounds on the rare tau decay. Physical conculsions unchange
Physics potential of the ESSÎœSB
The ESSÎœSB project proposes to base a neutrino âSuper Beamâ of unprecedented luminosity at the European Spallation Source. The original proposal identified the second peak of the oscillation probability as the optimal to maximize the discovery potential to leptonic CP violation. However this choice reduces the statistics at the detector and penalizes other complementary searches such as the determination of the atmospheric oscillation parameters, particularly the octant of Ξ23 as well as the neutrino mass ordering. We explore how these shortcomings can be alleviated by the combination of the beam data with the atmospheric neutrino sample that would also be collected at the detector. We find that the combination not only improves very significantly these drawbacks, but also enhances both the CP violation discovery potential and the precision in the measurement of the CP violating phase, for which the facility was originally optimized, by lifting parametric degeneracies. We then reassess the optimization of the ESSÎœSB setup when the atmospheric neutrino sample is considered, with an emphasis in performing a measurement of the CP violating phase as precise as possible. We find that for the presently preferred value of Ύ⌠- Ï/ 2 , shorter baselines and longer running time in neutrino mode would be optimal. In these conditions, a measurement better than 14Âș â would be achievable for any value of the Ξ23 octant and the mass ordering. Conversely, if present and next generation facilities were not able to discover CP violation, longer baselines and more even splitting between neutrino and neutrino modes would be preferable. These choices would allow a 5 Ï discovery of CP violation for around a 60 % of the possible values of ÎŽ and to determine its value with a precision around 6 â if it is close to 0 or ÏThis work is supported in part by the European Unionâs Horizon 2020 research and innovation programme under the Marie SklodowskaCurie Grant agreements 674896-Elusives, 690575-InvisiblesPlus, and 777419-ESSnuSB, as well as by the COST Action CA15139 EuroNuNet. MB, EFM, and SR acknowledge support from the âSpanish Agencia Estatal de InvestigaciĂłnâ (AEI) and the EU âFondo Europeo de Desarrollo Regionalâ (FEDER) through the project FPA2016-78645- P; and the Spanish MINECO through the âRamĂłn y Cajalâ programme and through the Centro de Excelencia Severo Ochoa Program under Grant SEV-2016-059
Morphological and geochemical features of crater lakes in Costa Rica: an overview.
This paper describes the compositional and morphological features of the crater lakes found in the volcanoes of RincĂłn de La Vieja, PoĂĄs, IrazĂș, Congo and Tenorio volcanoes (Costa Rica). As evidenced by the distribution of the water and dissolved gas chemistry along vertical profiles, the different fluid sources feeding the lakes reflect the present status of each of the volcanic systems. The chemical features of the Caliente (PoĂĄs volcano) and RincĂłn crater (RincĂłn de la Vieja volcano) lakes are mainly dependent on i) inputs of magmatic fluids from sub-lacustrine fumaroles and ii) water-rock interaction processes. Conversely, the IrazĂș lake is mainly affected by the presence of CO2(H2S)-rich fluids discharged from a hydrothermal system, which masked possible magmatic fluid contributions. Rainfall and organic activity are the main factors responsible for the chemical composition of Hule, Botos, Congo and Tenorio lakes. The chemical and isotopic water composition of Botos, IrazĂș and Hule lakes have displayed no significant variations along the vertical profiles. In contrast, Caliente lake shows a distinctive chemical stratification, mainly involving F-, Cl- and SO4 2-. The behaviour of these compounds seems to be governed by both dissolution of highly acidic species, i.e. HF, HCl and SO2 released from the magmatic environment, and microbial activity. Despite the significant increases with depth of dissolved CO2 at Caliente and IrazĂș lakes, the hazard for Nyos-type gas eruptions can be considered negligible, since i) the water volumes are too small and ii) the convective heat transfer limits the CO2 recharge rate. The relatively high concentrations of dissolved CO2 measured at the maximum depth of the Hule lake are likely produced by both degradation of organic material and degassing from a deep source. The sporadic episodes of fish deaths recently observed in this lake can be associated with lake overturn processes that have favoured the rise up to the lake surface of deep, oxygen-depleted waters.Journal of limnolog
Bilateral Internuclear Ophthalmoplegia in a Patient with Devic's Neuromyelitis Optica
An unusual presentation of Devic's neuromyelitis optica (NMO) disease associated with bilateral internuclear ophthalmoplegia (INO) is described. A 32-year-old pregnant patient was diagnosed with NMO. First symptoms were headache and sudden visual loss in her right eye (RE). Eighteen months ago, she reported other neurologic symptoms such as paresthesia. Based on her visual field, fundoscopy and Ishihara test, she was diagnosed with retrobulbar neuritis of the RE. After delivery, new neurologic symptoms resembling transverse myelitis appeared. She was treated with methylprednisolone and plasmapheresis, which improved her visual acuity; however, a sudden bilateral INO appeared, with adduction defect and nystagmus with abduction in both eyes. No improvement was obtained after treatment with azathioprine and rituximab. Paresis of the legs and the right arm persisted, but double vision and OIN gradually disappeared. At the end, the patient had a residual exophoria in the RE and nystagmus with abduction in the left eye. Prevalence of NMO is lower than one case per one million inhabitants, and it is not likely to affect the encephalic trunk; furthermore, bilateral INO in NMO is rare. Two major criteria and at least two of the three minor ones are required to confirm a NMO diagnosis, and our patient fulfilled these diagnosis criteria
Mechanisms and kinetics of C-S-H nucleation approaching the spinodal line: Insights into the role of organics additives
Wet chemistry C-S-H precipitation experiments were performed under controlled
conditions of solution supersaturation in the presence and absence of gluconate
and three hexitol molecules. Characterization of the precipitates with SAXS and
cryo-TEM experiments confirmed the presence of a multi-step nucleation pathway.
Induction times for the formation of the amorphous C-S-H spheroids were
determined from light transmittance. Analysis of those data with the classical
nucleation theory revealed a significant increase of the kinetic prefactor in
the same order as the complexation constants of calcium and silicate with each
of the organics. Finally, two distinct precipitation regimes of the C-S-H
amorphous precursor were identified: i) a nucleation regime at low saturation
indexes (SI) and ii) a spinodal nucleation regime at high SI where the free
energy barrier to the phase transition is found to be of the order of the
kinetic energy or less.Comment: Accepted in Cement and Concrete Research. 30 pages plus supplementary
materials. arXiv admin note: substantial text overlap with arXiv:2111.0274
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