2,703 research outputs found
La educación inclusiva frente a las desigualdades sociales: un estado de la cuestion y algunas reflexiones geograficas
Este artículo establece un estado de la cuestión e la educación inclusiva en el mundo y sugiere algunas reflexiones al respecto. El primer apartado recuerda las conexiones ineludibles entre las preocupaciones educativas por la educación inclusiva y las preocupaciones más generales por la desigualdad. El segundo consigna los criterios de búsqueda de las publicaciones académicas, y observa dos grandes temas en sus contenidos: sobre todo, el cambio interno de las escuelas atrae las miradas, pero en segundo plano también el entorno territorial despierta algunas inquietudes. El tercero anota los criterios de búsqueda de la documentación del Banco Mundial, la OCDE y la UNESCO. En este ámbito los simposios de la Oficina Internacional de la Educación de UNESCO revelan una interpretación dispar, aunque convergente, del concepto de educación inclusiva en las distintas regiones mundiales. Asimismo, todas las publicaciones oficiales muestran una atención prioritaria a las dinámicas internas de las escuelas, puesto que apenas algunas esbozan ciertas relaciones entre la educación inclusiva y las políticas públicas. El último apartado adelanta varios argumentos a favor de una mayor consideración de las escalas local y estatal de la educación inclusiva. Las principales razones para atender a la dimensión local provienen de la causalidad acumulativa de las privaciones sociales, de la necesidad de articular la acción de las escuelas y de la posibilidad de abrir un espacio significativo para la participación ciudadana. Asimismo, las principales razones para atender a la dimensión estatal surgen de las posibles sinergias entre la educación inclusiva y la expansión educativa (p. ej. ¿es correlativo el avance de la escolarización en los distintos ciclos escolares?) como también entre la educación inclusiva y la protección social (p. ej. ¿tienen una implicación pedagógica consistente las abundantes condiciones educativas de las transferencias sociales?
Deployment requirements for deorbiting electrodynamic tether technology
In the last decades, green deorbiting technologies have begun to be investigated and have raised a great interest in the space community. Among the others, electrodynamic tethers appear to be a promising option. By interacting with the surrounding ionosphere, electrodynamic tethers generate a drag Lorentz force to decrease the orbit altitude of the satellite, causing its re-entry in the atmosphere without using propellant. In this work, the requirements that drive the design of the deployment mechanism proposed for the H2020 Project E.T.PACK\u2014Electrodynamic Tether Technology for Passive Consumable-less Deorbit Kit\u2014are presented and discussed. Additionally, this work presents the synthesis of the reference profiles used by the motor of the deployer to make the tethered system reach the desired final conditions. The result is a strategy for deploying electrodynamic tape-shaped tethers used for deorbiting satellites at the end of their operational life
Deorbit kit demonstration mission
In Low Earth Orbit, it is possible to use the ambient plasma and the geomagnetic field to exchange momentum with the Earth's magnetosphere without using propellant. A device that allows an efficient momentum exchange is the electrodynamic tether (EDT), a long conductor attached to the satellite. EDT technology has been demonstrated in several past missions, being the Plasma Motor Generator mission (NASA 1993) one of the most successful. Nevertheless, it is not until today that reality has imposed a strong need and a concrete use case for developing this technology. In March 2019, the European Commission project Electrodynamic Tether technology for PAssive Consumable-less deorbit Kit (E.T.PACK) started the design of a new generation EDT. After completing the design phase, the consortium manufactured and is currently testing a Deorbit Kit Demonstrator (DKD) breadboard based on EDT technology. The objective of E.T.PACK is to reach Technology Readiness Level equal to 4 by 2022. The DKD is a standalone 24-kg satellite with the objective to demonstrate the performances of the improved EDT solution and validate its ultra-compact deployment system. The DKD is composed of two modules that will separate in orbit extending a 500-m long tape-like tether. The deployed bare-Aluminium tether will capture electrons from the ambient plasma passively and the circuit will be closed with the ionospheric plasma by using an active electron emitter. E.T.PACK tether will take advantage of several novelties with respect to the mission flown in the past that will allow to optimize the system volume and mass. Once successful demonstrated in orbit, the team plans to develop a suite of EDT systems capable of deorbiting satellites between 200 and 1000 kg from an altitude up to 1200 km in a few months. The work presents the current design status of the de-orbit kit demonstrator breadboard, the simulations of the system deorbit performances and the development approach.This work was supported by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No.828902 (3M€ E.T.PACK project) and No.101034874 (100K€ BMOM project). SG is supported by an Industrial Ph.D funded by Comunidad de Madrid (135K€ IND2019/TIC17198). The team has recently got 2.5M€ additional financial support from European Union (ETPACK-F project No. 101058166) for the manufacturing and qualification of the In Orbit Demonstration (IOD) by the end of 2025
Luminosity determination using Z boson production at the CMS experiment
The measurement of Z boson production is presented as a method to determine the integrated luminosity of CMS data sets. The analysis uses proton–proton collision data, recorded by the CMS experiment at the CERN LHC in 2017 at a center-of-mass energy of 13 TeV . Events with Z bosons decaying into a pair of muons are selected. The total number of Z bosons produced in a fiducial volume is determined, together with the identification efficiencies and correlations from the same data set, in small intervals of 20 pb-1 of integrated luminosity, thus facilitating the efficiency and rate measurement as a function of time and instantaneous luminosity. Using the ratio of the efficiency-corrected numbers of Z bosons, the precisely measured integrated luminosity of one data set is used to determine the luminosity of another. For the first time, a full quantitative uncertainty analysis of the use of Z bosons for the integrated luminosity measurement is performed. The uncertainty in the extrapolation between two data sets, recorded in 2017 at low and high instantaneous luminosity, is less than 0.5%. We show that the Z boson rate measurement constitutes a precise method, complementary to traditional methods, with the potential to improve the measurement of the integrated luminosity
Elliptic anisotropy measurement of the f0(980) hadron in proton-lead collisions and evidence for its quark-antiquark composition
Despite the f0(980) hadron having been discovered half a century ago, the
question about its quark content has not been settled: it might be an ordinary
quark-antiquark (qq) meson, a tetraquark (qqqq) exotic state, a kaon-antikaon
(KK) molecule, or a quark-antiquark-gluon (qqg) hybrid. This paper reports
strong evidence that the f0(980) state is an ordinary qq meson, inferred from
the scaling of elliptic anisotropies (v2) with the number of constituent quarks
(nq), as empirically established using conventional hadrons in relativistic heavy
ion collisions. The f0(980) state is reconstructed via its dominant decay
channel f0(980) → π+π−, in proton-lead collisions recorded by the CMS
experiment at the LHC, and its v2 is measured as a function of transverse
momentum (pT). It is found that the nq = 2 (qq state) hypothesis is favored over
nq = 4 (qqqq or KK states) by 7.7, 6.3, or 3.1 standard deviations in the pT < 10, 8,
or 6 GeV/c ranges, respectively, and over nq = 3 (qqg hybrid state) by
3.5 standard deviations in the pT < 8 GeV/c range. This result represents the
first determination of the quark content of the f0(980) state, made possible by
using a novel approach, and paves the way for similar studies of other exotic
hadron candidates
Search for Higgs boson pair production with one associated vector boson in proton-proton collisions at √s = 13 TeV
A search for Higgs boson pair (HH) production in association with a vector boson
V (W or Z boson) is presented. The search is based on proton-proton collision data at a
center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, corresponding
to an integrated luminosity of 138 fb−1
. Both hadronic and leptonic decays of V bosons
are used. The leptons considered are electrons, muons, and neutrinos. The HH production
is searched for in the bb ̄bb ̄ decay channel. An observed (expected) upper limit at 95%
confidence level of VHH production cross section is set at 294 (124) times the standard
model prediction. Constraints are also set on the modifiers of the Higgs boson trilinear
self-coupling, kλ, assuming k2V = 1, and vice versa on the coupling of two Higgs bosons
with two vector bosons, k2V. The observed (expected) 95% confidence intervals of these
coupling modifiers are −37.7 < kλ < 37.2 (−30.1 < kλ < 28.9) and −12.2 < k2V < 13.5
(−7.2 < k2V < 8.9), respectively
Operation and performance of the CMS silicon strip tracker with proton-proton collisions at the CERN LHC
Salient aspects of the commissioning, calibration, and performance of the CMS silicon strip tracker are discussed, drawing on experience during operation with proton-proton collisions delivered by the CERN LHC. The data were obtained with a variety of luminosities. The operating temperature of the strip tracker was changed several times during this period and results are shown as a function of temperature in several cases. Details of the system performance are presented, including occupancy, signal-to-noise ratio, Lorentz angle, and single-hit spatial resolution. Saturation effects in the APV25 readout chip preamplifier observed during early Run 2 are presented, showing the effect on various observables and the subsequent remedy. Studies of radiation effects on the strip tracker are presented both for the optical readout links and the silicon sensors. The observed effects are compared to simulation, where available, and they generally agree well with expectations
K0S andΛ(Λ ̅) two-particle femtoscopic correlations in PbPb collisions at √sNN = 5.02 TeV
Two-particle correlations are presented for K0S, Λ, and Λ ̄ strange hadrons as a function of relative momentum in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The dataset corresponds to an integrated luminosity of 0.607 nb−1 and was collected using the CMS detector at the CERN LHC. These correlations are sensitive to quantum statistics and to final-state interactions between the particles. The source size extracted from the K0SK0S correlations is found to decrease from 4.6 to 1.6 fm in going from central to peripheral collisions. Strong interaction scattering parameters (i.e., scattering length and effective range) are determined from the ΛK0S and ΛΛ (including their charge conjugates) correlations using the Lednický-Lyuboshitz model and are compared to theoretical and other experimental results
Search for central exclusive production of top quark pairs in proton-proton collisions at √s=13 TeV with tagged protons
A search for the central exclusive production of top quark-antiquark pairs (tt)
is performed for the frst time using proton-tagged events in proton-proton collisions at the
LHC at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity
of 29.4 fb−1
. The tt decay products are reconstructed using the central CMS detector,
while forward protons are measured in the CMS-TOTEM precision proton spectrometer. An
observed (expected) upper bound on the production cross section of 0.59 (1.14) pb is set at 95%
confdence level, for collisions of protons with fractional momentum losses between 2 and 20%
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