The Standard Model of particle physics is still lacking an understanding of the generation and nature of neutrino masses. A favorite theoretical scenario (the see-saw mechanism) is that both Dirac ...and Majorana mass terms are present, leading to the existence of heavy partners of the light neutrinos, presumably massive and nearly sterile. These heavy neutrinos can be searched for at high energy lepton colliders of very high luminosity, such as the Future electron-positron e+e− Circular Collider, FCC-ee (TLEP), presently studied within the Future Circular Collider design study at CERN, as a possible first step. A first look at sensitivities, both from neutrino counting and from direct search for heavy neutrino decay, are presented. The number of neutrinos Nν should be measurable with a precision of ΔNν≈±(0.0004–0.0010), while the direct search appears very promising due to the long lifetime of heavy neutrinos for small mixing angles. A sensitivity down to a heavy-light mixing of |U|2≃10−12 is obtained, covering a large phase space for heavy neutrino masses between 10 and 80 GeV/c2.
Following the launch of ESA's Soil Moisture and Ocean Salinity (SMOS) mission, it has been shown that brightness temperatures at a low microwave frequency of 1.4 GHz (L-band) are sensitive to sea ice ...properties. In the first demonstration study, sea ice thickness up to 50 cm has been derived using a semi-empirical algorithm with constant tie-points. Here, we introduce a novel iterative retrieval algorithm that is based on a thermodynamic sea ice model and a three-layer radiative transfer model, which explicitly takes variations of ice temperature and ice salinity into account. In addition, ice thickness variations within the SMOS spatial resolution are considered through a statistical thickness distribution function derived from high-resolution ice thickness measurements from NASA's Operation IceBridge campaign. This new algorithm has been used for the continuous operational production of a SMOS-based sea ice thickness data set from 2010 on. The data set is compared to and validated with estimates from assimilation systems, remote sensing data, and airborne electromagnetic sounding data. The comparisons show that the new retrieval algorithm has a considerably better agreement with the validation data and delivers a more realistic Arctic-wide ice thickness distribution than the algorithm used in the previous study (Kaleschke et al., 2012).
A prototype for the SHiP timing detector Betancourt, C.; Korzenev, A.; Mermod, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2020, Letnik:
979
Journal Article
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Odprti dostop
The proposed SHiP experiment located at the CERN SPS will search for feebly interacting particles with masses below 10 GeV/c2. A veto timing detector will reject combinatorial di-muon backgrounds by ...requiring event to be coincident in time within 100 ps. The baseline option for the timing detector consist of scintillating bars read out by arrays of silicon photomultipliers. The detector comprises 546 bars of EJ200 scintillating material with dimensions 168 cm × 6 cm × 1 cm broken into three columns and covering an active area of 5 m × 10 m. The end of each bar is read out by an array of eight silicon photomultipliers attached to custom PCBs and subsequently read out by a DAQ system based on a SAMPIC chip. We present test beam results on a single column 22 bar prototype for the SHiP timing detector. Measurements were taken at the T10 beam line of the CERN PS. A timing resolution across the detector is found to be about 90 ps. The particle identification capability using a time of flight method is also demonstrated.
We investigate the possibility of indirectly constraining the
B
+
→
K
+
τ
+
τ
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decay rate using precise data on the
B
+
→
K
+
μ
+
μ
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dimuon spectrum. To this end, we estimate the distortion of the ...spectrum induced by the
B
+
→
K
+
τ
+
τ
-
→
K
+
μ
+
μ
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re-scattering process, and propose a method to simultaneously constrain this (non-standard) contribution and the long-distance effects associated to hadronic intermediate states. The latter are constrained using the analytic properties of the amplitude combined with data and perturbative calculations. Finally, we estimate the sensitivity expected at the LHCb experiment with present and future datasets. We find that constraints on the branching fraction of
O
(
10
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3
)
, competitive with current direct bounds, can be achieved with the current dataset, while bounds of
O
(
10
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4
)
could be obtained with the LHCb upgrade-II luminosity.
Regional horizontal and vertical patterns of ocean kinetic energy (KE) during 1983–2018 are studied using a numerical simulation. The analysis is focused on time‐mean and transient components of KE. ...For understanding its contribution to the total as function of timescale, the transient part is further sub‐divided into six frequency bands, with periods >16 months, 16–8 months, 8–4 months, 4–1 months, 1 month–5 days and <5 days. Near the surface, besides intensification due to wind‐forced generation, transient KE is enhanced in boundary currents, in equatorial wave guides and in the Southern Ocean. In the deep, KE is enhanced in re‐circulation regions under boundary currents and at eastern sides of topographic ridges. On scales <5 days it is enhanced over shelf and in quiet ocean interior areas. The largest fraction of transient energy resides in the eddy‐populated band 1 week–4 months. Decadal changes of KE are associated with mean flow variations and changes on inter‐ and intra‐annual periods, especially in the Atlantic and Southern Oceans. Changes in the subpolar Atlantic are correlated with the North Atlantic Oscillation and in the Southern Ocean with the Southern Annular Mode. A decrease/increase in Atlantic/Pacific KE is noticed over the investigated period. Trends are found in the Gulf Stream, Kuroshio Current and along the Antarctic Circumpolar Current, which shows an increase in mean and transient energy in the Indian/west Pacific sectors and a decrease in the Atlantic sector. The strong variations between decades suggest that trends are part of multi‐decadal variability.
Plain Language Summary
Horizontal, vertical and temporal distributions of ocean kinetic energy (KE) during 1983–2018 are studied with a numerical simulation. We focus the time‐averaged and time‐varying KE, the latter sub‐divided into periods: >16 months, 16–8 months, 8–4 months, 4–1 months, 1 month–5 days and <5 days. KE is large in the upper ocean due to wind forcing and decreases with depth. It is large in currents along ocean western boundaries, in equatorial regions and along the Southern Ocean circumpolar current. In the deep, KE is large in re‐circulation regions under strong currents and at eastern sides of bottom topography. Variations <5 days are large over shelves and in the ocean interior away from boundary currents. The largest fraction of energy resides between 1 week and 4 months, where rotating water bodies are dominant. A decrease in Atlantic and increase in Pacific KE were noticed. Changes in subpolar Atlantic and in Southern Ocean are related to climate modes, namely the North Atlantic Oscillation and the Southern Annular Mode. The Southern Ocean shows an energy increase in the Indian/west‐Pacific sectors and a decrease in the Atlantic sector. Strong variations between decades suggest changes are part of longer timescale variations.
Key Points
Ocean kinetic energy (KE) is surface intensified. In the deep, it is enhanced primarily in the vicinity of topographic structures
The largest fraction of transient KE is found at eddy‐rich periods (1 week–3 months), showing a sustained decrease globally
Subpolar Atlantic KE changes are linked to the North Atlantic Oscillation and Southern Ocean changes to the Southern Annular Mode
To describe the prevalence and characteristics of interstitial lung abnormalities (ILA) in CT scans performed prior to the initiation of antifibrotics in a series of patients with interstitial lung ...disease (ILD), and to identify characteristics apparent on early CT scans that could help to predict outcomes.
We conducted a retrospective observational study. The original cohort consisted of 101 patients diagnosed with ILD and treated with antifibrotics in a tertiary hospital. Patients were included if they had a thoracic CT scan performed at least one year before initiation of therapy. They were classified radiologically in three groups: without ILA, with radiological ILA and extensive abnormalities. ILA were classified as subpleural fibrotic, subpleural non-fibrotic and non-subpleural. The initial scan and the latest CT scan performed before treatment were read for assessing progression. The relationship between CT findings of fibrosis and the radiological progression rate and mortality were analyzed.
We included 50 patients. Only 1 (2%) had a normal CT scan, 25 (50%) had extensive alterations and 24 (48%) had radiological criteria for ILA, a median of 98.2 months before initiation of antifibrotics, of them 18 (75%) had a subpleural fibrotic pattern. Significant bronchiectasis and obvious honeycombing in the lower zones were associated with shorter survival (p = 0.04). Obvious honeycombing in the lower zones was also significantly (p < 0.05) associated with a faster progression rate.
Fibrotic ILAs are frequent in remote scans of patients with clinically relevant ILD, long before they require antifibrotics. Findings of traction bronchiectasis and honeycombing in the earliest scans, even in asymptomatic patients, are related to mortality and progression later on.
Describir la prevalencia y características de las alteraciones intersticiales pulmonares (AIP) en tomografías computarizadas (TC) realizadas antes del inicio del tratamiento antifibrótico en una serie de pacientes con enfermedad pulmonar intersticial difusa (EPID), e identificar las características visibles en las TC iniciales que podrían ayudar a predecir el pronóstico.
Estudio observacional retrospectivo que incluye una cohorte original de 101 pacientes diagnosticados de EPID y tratados con antifibróticos en un hospital terciario. Los pacientes fueron incluidos cuando contaban con una TC torácica realizada al menos un año antes del inicio del tratamiento. Se clasificaron radiológicamente en tres grupos: sin AIP, con AIP y “alteraciones extensas”. Asimismo, las AIP se clasificaron como subpleural fibrótica, subpleural no fibrótica y no subpleural. Se leyeron la TC inicial y la más cercana anterior al tratamiento para evaluar la progresión, y se analizó la relación entre los hallazgos de fibrosis en dicha TC inicial y la tasa de progresión radiológica y mortalidad.
Se incluyeron 50 pacientes, solo 1 (2%) tenía una TC inicial normal, 25 (50%) tenían “alteraciones extensas” y 24 (48%) tenían criterios de AIP radiológica una mediana de 98,2 meses antes del inicio del tratamiento. De estas últimas, 18 (75%) tenían un patrón subpleural fibrótico. Las bronquiectasias significativas y el panal evidente en las zonas inferiores se asociaron con una supervivencia más corta (p = 0,04). El panal en las zonas inferiores se asoció significativamente (p < 0,05) con una tasa de progresión más rápida.
Las AIP fibróticas son frecuentes en exploraciones antiguas de pacientes con EPID clínicamente relevante, mucho antes de que requieran tratamiento con antifibróticos. Los hallazgos de bronquiectasias por tracción y panal en las TC iniciales, incluso en pacientes asintomáticos, se relacionan con la mortalidad y progresión más rápida en el futuro.
The regional ocean modeling system is used, at a resolution of 1/12°, to explicitly simulate the ocean circulation near the Iberian coast during two 30-year simulations forced by atmospheric fields ...produced by the RACMO regional climate model. The first simulation is a control run for the present climate (1961–1990) and the second is a scenario run from the IPCC A2 scenario (2071–2100). In the control run, the model reproduces some important features of the regional climate but with an overestimation of upwelling intensity, mainly attributable to inaccuracies in the coastal wind distributions when compared against reanalysis data. A comparison between the scenario and control simulations indicates a significant increase in coastal upwelling, with more frequent events with higher intensity, leading to an overall enhancement of SST variability on both the intra- and inter-annual timescales. The increase in upwelling intensity is more prominent in the northern limit of the region, near cape Finisterre, where its mean effect extends offshore for a few hundred kms, and is able to locally cancel the effect of global warming. If these results are confirmed, climate change will have a profound impact on the regional marine ecosystem.
The LUMIRA trial evaluated the effectiveness of radiofrequency (RFA) and microwave ablation (MWA) in lung tumours ablation and defining more precisely their fields of application. It is a controlled ...prospective multi-centre random trial with 1:1 randomization. Fifty-two patients in stage IV disease (15 females and 37 males, mean age 69 y.o., range 40–87) were included. We randomized the patients in two different subgroups: MWA group and RFA group. For each group, we evaluated the technical and clinical success, the overall survival and complication rate. Inter-group difference was compared using Chi-square test or Fisher’s exact test for categorical variables and one-way ANOVA test for continuous variables. For RFA group, there was a significant reduction in tumour size only between 6 and 12 months (
p
value = 0.0014). For MWA group, there was a significant reduction in tumour size between 6 and 12 months (
p
value = 0.0003) and between pre-therapy and 12 months (
p
value = 0.0215). There were not significant differences between the two groups in terms of survival time (
p
value = 0.883), while the pain level in MWA group was significantly less than in RFA group (1.79 < 3.25,
p
value = 0.0043). In conclusion, our trial confirms RFA and MWA are both excellent choices in terms of efficacy and safety in lung tumour treatments. However, when compared to RFA therapy, MWA produced a less intraprocedural pain and a significant reduction in tumour mass.
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