925 research outputs found
Can serious games help to mitigate climate change? Exploring their influence on Spanish and American teenagers’ attitudes
Es urgente y necesario reducir las emisiones de gases de efecto invernadero y mitigar el cambio climático, y esta lucha requiere un cambio en las actitudes de los adolescentes. En la búsqueda de nuevos enfoques dirigidos a los jóvenes, los serious games en formato online parecen una prometedora herramienta de comunicación y educación. Basándonos en el juego 2020 Energy como estudio de caso, el principal objetivo de este artículo es examinar la influencia de dicho juego sobre las actitudes de adolescentes españoles y estadounidenses (N = 108), empleando un diseño pretest-posttest con una condición experimental (jugar al juego) y una condición de control (no jugar al juego). Los resultados muestran que no había diferencias estadísticamente significativas después de jugar al juego, aunque una observación más detallada de cada factor ofrece algunas consecuencias positivas.There is an urgent need to curb emissions and mitigate climate change, and this fight requires a change in teenagers’ attitudes. In search of new approaches targeting youth, online games are seen as a promising tool for communication and education. Using the serious game 2020 Energy as a case study, the main objective of this paper is to examine the influence of the game on Spanish and American teenagers’ attitudes (N = 108), employing a pretest-posttest design with an experimental condition (playing the game) and a control condition (not playing the game). Results show that there have not been statistically significant differences after playing the game, although when looking closer at each factor, some positive consequences can be found.HUM466 Acceso y evaluación de la información científic
Measurement of the Luminosity in the ZEUS Experiment at HERA II
The luminosity in the ZEUS detector was measured using photons from electron
bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher
luminosity. At the same time the luminosity-measuring system of the ZEUS
experiment was modified to tackle the expected higher photon rate and
synchrotron radiation. The existing lead-scintillator calorimeter was equipped
with radiation hard scintillator tiles and shielded against synchrotron
radiation. In addition, a magnetic spectrometer was installed to measure the
luminosity independently using photons converted in the beam-pipe exit window.
The redundancy provided a reliable and robust luminosity determination with a
systematic uncertainty of 1.7%. The experimental setup, the techniques used for
luminosity determination and the estimate of the systematic uncertainty are
reported.Comment: 25 pages, 11 figure
Molecular Mechanism of Capacitative Calcium Entry Deficits in Familial Alzheimer’s Disease
Poster PresentationPresenilin (PS) is the catalytic subunit of the gamma-secretase which is responsible for the cleavage of
amyloid precursor protein to form beta amyloid (Aβ). Mutations in PS associated with familial
Alzheimer’s disease (FAD) increase the Aβ plaques formation in the brain and cause neurodegeneration.
Apart from this, FAD-linked PS mutations have been demonstrated to disrupt intracellular calcium (Ca2+)
regulation. Accumulating evidence suggests that Ca2+ disruption may play a proximal role in the AD
pathogenesis. Mutant PS exaggerated Ca2+ release from the endoplasmic reticulum (ER). It also attenuated
Ca2+ entry through the capacitative Ca2+ entry (CCE) pathway, yet, the mechanism is not fully understood.
Using a human neuroblast cell line SH-SY5Y and Ca2+ imaging technique, we observed CCE deficits in
FAD-linked PS1-M146L retroviral infected cell. The attenuation of CCE in PS1 mutant cells was not
mediated by the down-regulation of STIM1 and Orai1 expression, the known essential molecular players
in the CCE pathway. Instead, we identified a molecular interaction between PS and STIM1 proteins by
immunoprecipitation. On the other hand, immunofluorescence staining showed a significant reduction in
puncta formation after ER Ca2+ depleted by thapsigargin in cells infected with PS1-M146L as compared to
the wild type PS1 infected cells. Taken together, our results suggest a molecular mechanism for the CCE
deficits in FAD associated with PS1 mutations. The interaction of mutant PS1 with STIM1 exerts a
negative impact on its oligomerization and/or its interaction with Orai1. Our results may suggest molecular
targets for the development of therapeutic agents that help to treat the disease.published_or_final_versio
A Search for Jet Handedness in Hadronic Decays
We have searched for signatures of polarization in hadronic jets from decays using the ``jet handedness'' method. The polar angle
asymmetry induced by the high SLC electron-beam polarization was used to
separate quark jets from antiquark jets, expected to be left- and
right-polarized, respectively. We find no evidence for jet handedness in our
global sample or in a sample of light quark jets and we set upper limits at the
95% C.L. of 0.063 and 0.099 respectively on the magnitude of the analyzing
power of the method proposed by Efremov {\it et al.}Comment: Revtex, 8 pages, 2 figure
Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment
The OLYMPUS collaboration reports on a precision measurement of the
positron-proton to electron-proton elastic cross section ratio, ,
a direct measure of the contribution of hard two-photon exchange to the elastic
cross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams
were directed through a hydrogen gas target internal to the DORIS storage ring
at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and
time-of-flight scintillators detected elastically scattered leptons in
coincidence with recoiling protons over a scattering angle range of to . The relative luminosity between the two beam species
was monitored using tracking telescopes of interleaved GEM and MWPC detectors
at , as well as symmetric M{\o}ller/Bhabha calorimeters at
. A total integrated luminosity of 4.5~fb was collected. In
the extraction of , radiative effects were taken into account
using a Monte Carlo generator to simulate the convolutions of internal
bremsstrahlung with experiment-specific conditions such as detector acceptance
and reconstruction efficiency. The resulting values of , presented
here for a wide range of virtual photon polarization ,
are smaller than some hadronic two-photon exchange calculations predict, but
are in reasonable agreement with a subtracted dispersion model and a
phenomenological fit to the form factor data.Comment: 5 pages, 3 figures, 2 table
Measurement of inclusive D*+- and associated dijet cross sections in photoproduction at HERA
Inclusive photoproduction of D*+- mesons has been measured for photon-proton
centre-of-mass energies in the range 130 < W < 280 GeV and a photon virtuality
Q^2 < 1 GeV^2. The data sample used corresponds to an integrated luminosity of
37 pb^-1. Total and differential cross sections as functions of the D*
transverse momentum and pseudorapidity are presented in restricted kinematical
regions and the data are compared with next-to-leading order (NLO) perturbative
QCD calculations using the "massive charm" and "massless charm" schemes. The
measured cross sections are generally above the NLO calculations, in particular
in the forward (proton) direction. The large data sample also allows the study
of dijet production associated with charm. A significant resolved as well as a
direct photon component contribute to the cross section. Leading order QCD
Monte Carlo calculations indicate that the resolved contribution arises from a
significant charm component in the photon. A massive charm NLO parton level
calculation yields lower cross sections compared to the measured results in a
kinematic region where the resolved photon contribution is significant.Comment: 32 pages including 6 figure
Limits on the effective quark radius from inclusive scattering at HERA
The high-precision HERA data allows searches up to TeV scales for Beyond the
Standard Model contributions to electron-quark scattering. Combined
measurements of the inclusive deep inelastic cross sections in neutral and
charged current scattering corresponding to a luminosity of around 1
fb have been used in this analysis. A new approach to the beyond the
Standard Model analysis of the inclusive data is presented; simultaneous
fits of parton distribution functions together with contributions of "new
physics" processes were performed. Results are presented considering a finite
radius of quarks within the quark form-factor model. The resulting 95% C.L.
upper limit on the effective quark radius is cm.Comment: 10 pages, 4 figures, accepted by Phys. Lett.
Measurement of Jet Shapes in Photoproduction at HERA
The shape of jets produced in quasi-real photon-proton collisions at
centre-of-mass energies in the range GeV has been measured using the
hadronic energy flow. The measurement was done with the ZEUS detector at HERA.
Jets are identified using a cone algorithm in the plane with a
cone radius of one unit. Measured jet shapes both in inclusive jet and dijet
production with transverse energies GeV are presented. The jet
shape broadens as the jet pseudorapidity () increases and narrows
as increases. In dijet photoproduction, the jet shapes have been
measured separately for samples dominated by resolved and by direct processes.
Leading-logarithm parton-shower Monte Carlo calculations of resolved and direct
processes describe well the measured jet shapes except for the inclusive
production of jets with high and low . The observed
broadening of the jet shape as increases is consistent with the
predicted increase in the fraction of final state gluon jets.Comment: 29 pages including 9 figure
Measurement of the diffractive structure function in deep inelastic scattering at HERA
This paper presents an analysis of the inclusive properties of diffractive
deep inelastic scattering events produced in interactions at HERA. The
events are characterised by a rapidity gap between the outgoing proton system
and the remaining hadronic system. Inclusive distributions are presented and
compared with Monte Carlo models for diffractive processes. The data are
consistent with models where the pomeron structure function has a hard and a
soft contribution. The diffractive structure function is measured as a function
of \xpom, the momentum fraction lost by the proton, of , the momentum
fraction of the struck quark with respect to \xpom, and of . The \xpom
dependence is consistent with the form \xpoma where
in all bins of and
. In the measured range, the diffractive structure function
approximately scales with at fixed . In an Ingelman-Schlein type
model, where commonly used pomeron flux factor normalisations are assumed, it
is found that the quarks within the pomeron do not saturate the momentum sum
rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil
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