3,085 research outputs found
EstrellaNueva: an open-source software to study the interactions and detection of neutrinos emitted by supernovae
Supernovae emit large fluxes of neutrinos which can be detected by detectors
on Earth. Future tonne-scale detectors will be sensitive to several neutrino
interaction channels, with thousands of events expected if a supernova emerges
in the galaxy neighborhood. There is a limited number of tools to study the
interaction rates of supernova neutrinos, although a plethora of available
supernova models exists. EstrellaNueva is an open-source software to calculate
expected rates of supernova neutrinos in detectors using target materials with
typical compositions, and additional compositions can be easily added. This
software considers the flavor transformation of neutrinos in the supernova
through the adiabatic Mikheyev--Smirnov--Wolfenstein effect, and their
interaction in detectors through several channels. Most of the interaction
cross sections have been analytically implemented, such as neutrino-electron
and neutrino-proton elastic scattering, inverse beta decay, and coherent
elastic neutrino-nucleus scattering. This software provides a link between
supernova simulations and the expected events in detectors by calculating
fluences and event rates to ease any comparison between theory and observation.
It provides a simple and standalone tool to explore many physics scenarios
offering an option to add analytical cross sections and define any target
material
Using synchronization to improve earthquake forecasting in a cellular automaton model
A new forecasting strategy for stochastic systems is introduced. It is
inspired by the concept of anticipated synchronization between pairs of chaotic
oscillators, recently developed in the area of Dynamical Systems, and by the
earthquake forecasting algorithms in which different pattern recognition
functions are used for identifying seismic premonitory phenomena. In the new
strategy, copies (clones) of the original system (the master) are defined, and
they are driven using rules that tend to synchronize them with the master
dynamics. The observation of definite patterns in the state of the clones is
the signal for connecting an alarm in the original system that efficiently
marks the impending occurrence of a catastrophic event. The power of this
method is quantitatively illustrated by forecasting the occurrence of
characteristic earthquakes in the so-called Minimalist Model.Comment: 4 pages, 3 figure
Describing soil surface microrelief by crossover length and fractal dimension
International audienceAccurate description of soil surface topography is essential because different tillage tools produce different soil surface roughness conditions, which in turn affects many processes across the soil surface boundary. Advantages of fractal analysis in soil microrelief assessment have been recognised but the use of fractal indices in practice remains challenging. There is also little information on how soil surface roughness decays under natural rainfall conditions. The objectives of this work were to investigate the decay of initial surface roughness induced by natural rainfall under different soil tillage systems and to compare the performances of a classical statistical index and fractal microrelief indices. Field experiments were performed on an Oxisol at Campinas, São Paulo State (Brazil). Six tillage treatments, namely, disc harrow, disc plow, chisel plow, disc harrow + disc level, disc plow + disc level and chisel plow + disc level were tested. Measurements were made four times, firstly just after tillage and subsequently with increasing amounts of natural rainfall. Duplicated measurements were taken per treatment and date, yielding a total of 48 experimental surfaces. The sampling scheme was a square grid with 25×25 mm point spacing and the plot size was 1350×1350 mm, so that each data set consisted of 3025 individual elevation points. Statistical and fractal indices were calculated both for oriented and random roughness conditions, i.e. after height reading have been corrected for slope and for slope and tillage tool marks. The main drawback of the standard statistical index random roughness, RR, lies in its no spatial nature. The fractal approach requires two indices, fractal dimension, D, which describes how roughness changes with scale, and crossover length, l, specifying the variance of surface microrelief at a reference scale. Fractal parameters D and l, were estimated by two independent self-affine models, semivariogram (SMV) and local root mean square (RMS). Both algorithms, SMV and RMS, gave equivalent results for D and l indices, irrespective of trend removal procedure, even if some bias was present which is in accordance with previous work. Treatments with two tillage operations had the greatest D values, irrespective of evolution stage under rainfall and trend removal procedure. Primary tillage had the greatest initial values of RR and l. Differences in D values between treatments with primary tillage and those with two successive tillage operations were significant for oriented but not for random conditions. The statistical index RR and the fractal indices l and D decreased with increasing cumulative rainfall following different patterns. The l and D decay from initial value was very sharp after the first 24.4 mm cumulative rainfall. For five out of six tillage treatments a significant relationship between D and l was found for the random microrelief conditions allowing a covariance analysis. It was concluded that using RR or l together with D best allow joint description of vertical and horizontal soil roughness variations
Introducción de demostraciones prácticas para la enseñanza de la física en las aulas universitarias
An analysis about utility, characteristics and structure of the so called «practical demonstrations» is presented in order to introduce a dynamic element in the classroom. Although in apparent contradiction with didactic modern trends that proclaim «what students are able to do by themselves, teachers should not do "practical demonstrations" should be placed in an active methodological approach as a complement in the exposition of the contents, getting some importance concerning student passivity, lack of didactic facilities and high number of students per classroom
Decision-making in school-age sport measured through a digital tool.
El objetivo de este estudio ha sido doble. Por un lado, diseñar y crear un
software de evaluación de toma de decisiones en edad escolar, en base a
aspectos espacio-temporales, contextualizado en voleibol, denominado “Juego
Interactivo de Voleibol”. Por otro lado, analizar y establecer su fiabilidad y validez.
El software diseñado se aplicó a una muestra de 132 escolares (64 niños y 68
niñas) de entre 10 y 13 años, de los centros educativos públicos de Educación
Primaria y Secundaria de las localidades sevillanas de Arahal y Paradas
(España). Para determinar la fiabilidad se estudió la consistencia interna a través
del coeficiente alfa de Cronbach. Para calcular el número óptimo de repeticiones
se utilizó el Coeficiente de Correlación Intraclase. La validez se comprobó en
base a la evaluación de un grupo de 5 expertos. Los resultados indicaron que
este nuevo software de evaluación alcanza altos niveles de fiablidad y validezThe aim of this study was twofold. On the one hand, the design and creation of
an evaluation software for decision-making in school-age children based on
spatial-temporal aspects in the context of volleyball called ‘Interactive Volleyball
Game’. On the other hand, the analysis and establishment of its reliability and
validity. The designed software was applied to a sample of 132 students (64
boys and 68 girls) aged between 10 and 13 years in public Elementary and
Secondary Education schools of Seville towns, Arahal and Paradas (Spain). To
determine the reliability, internal consistency was studied through Cronbach's
alpha. The intraclass correlation coefficient (ICC) was also analyzed to calculate
the optimal number of repetitions for future research. The validity was tested
based on the assessment of a group of 5 experts. The results indicated that this
new evaluation software reaches high levels of reliability and validit
Molecular-frame photoelectron angular distributions of CO in the vicinity of feshbach resonances: an xchem approach
The advent of ultrashort XUV pulses is pushing for the development of accurate theoretical calculations to describe ionization of molecules in regions where electron correlation plays a significant role. Here, we present an extension of the XCHEM methodology to evaluate laboratory- and molecular-frame photoelectron angular distributions in the region where Feshbach resonances are expected to appear. The performance of the method is demonstrated in the CO molecule, for which information on Feshbach resonances is very scarce. We show that photoelectron angular distributions are dramatically affected by the presence of resonances, to the point that they can completely reverse the preferred electron emission direction observed in direct nonresonant photoionization. This is the consequence of significant changes in the electronic structure of the molecule when resonances decay, an effect that is mostly driven by electron correlation in the ionization continuum. The present methodology can thus be helpful for the interpretation of angularly resolved photoionization time delays in this and more complex moleculesThe work was supported by the European COST Action AttoChem (CA18222) and the Spanish State Research Agency (AEI/ 10.13039/501100011033), Grants PID2019-105458RB-I00 and PID2019-106732GB-I00, “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2016-0686) and “María de Maeztu” Programme for Units of Excellence in R&D (CEX2018-000805-M
Effects of Mobility Programmes on University Students' Academic Performance
[EN] The number of students participating in mobility programmes has increased enormously over the years. The reasons are diverse and may range from personal growth to better employability prospects, together with improvement in foreign language skills and intercultural awareness. Mobility programmes receive generous funding from the European Commission, therefore their outcomes should be measured and evaluated. This paper focuses on a specific one: the academic effects of mobility programmes. We analyse whether there is an improvement in the academic performance of the students who participate in mobility programmes and, if this is the case, whether it is sustained over time. We use a broad dataset of students from the Faculty of Economics of the University of Valencia over a period of thirteen academic years. The results indicate that students participating in a mobility programme experiment a marked improvement in their scores at the host university, but this upgrading: a) is not homogeneous across the mobility programs or geographical areas considered; and b) partially vanishes off when the students come back to their home university.http://ocs.editorial.upv.es/index.php/HEAD/HEAD18González-Baixauli, C.; Montañes-Brunet, E.; Pérez-Vázquez, PJ. (2018). Effects of Mobility Programmes on University Students' Academic Performance. Editorial Universitat Politècnica de València. 553-562. https://doi.org/10.4995/HEAD18.2018.8034OCS55356
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