2,320 research outputs found
Car-following techniques: reconsidering the role of the human factor
Keeping correct distance between vehicles is a fundamental tenet in road traffic. New road signs and markings appearing on motorways aid drivers in determining this distance. However, the ‘Nagoya experiment’ (Sugiyama et al., 2008) revealed correct distance made following safe while also eventually destabilizing traffic flow. When traffic becomes dense, most drivers keep the minimum safety distance and brake when the vehicle ahead decelerates. The resultant chain reaction along the entire line of closely following vehicles causes for no apparent reason a traffic stoppage, known as a ‘phantom’ or ‘shockwave’ jam. The car-following models of Sugiyama et al. found certain speeds, traffic densities, and inter-vehicular distances combined to congest traffic. Drawing upon these and other phenomena (e.g., wave movement in Nature), car following by Driving to keep Inertia (DI) was conceived by us as an alternative to Driving to keep Distance (DD). Three studies explored possible prevention of ‘phantom’ jams by adopting DI. Using a driving simulator, affective and behavioural measures were taken (N=113). The results comparing the efficiency of DI vs. DD are summarized. DI promoted a more stable driver
trajectory, in cognitive-affective and behavioural terms, and lowered fuel consumption by about 20%
Comparación de la comprensión lectora en alumnos de cuarto año de secundaria de centros educativos estatales y no estatales de Lima Metropolitana
Revista de Investigación en Psicología, Vol. 13, No. 1Objetivos: a. Estudiar el desarrollo de la comprensión lectora en alumnos de cuarto año
de secundaria. b. Analizar el nivel de desarrollo de la comprensión de los alumnos de
centros educativos estatales y no estatales en cuarto de secundaria. c. Comparar el nivel de desarrollo de la comprensión lectora por género en cuarto año de secundaria. d. Establecer las propiedades psicométricas del instrumento utilizado. e. Construir los baremos para los alumnos del cuarto año de secundaria, considerando las variables género y tipo de gestión del centro educativo. f. Estudiar el modelo del constructo de la comprensión lectora utilizando el análisis factorial confirmatorio. Diseño: Estudio descriptivo comparativo, llevado a cabo en alumnos de cuarto año de secundaria considerando centros educativos estatales y no estatales, y considerando el género. Material y Métodos: Muestreo por conglomerados en dos etapas, con probabilidades proporcionales al tamaño; la muestra estuvo constituida por 613 participantes de las siete UGEL de Lima Metropolitana. Se elaboró una Prueba de Comprensión Lectora para el cuarto de secundaria. Se llevó a cabo el estudio psicométrico del instrumento para evaluar la validez y la confiabilidad. Asimismo, se llevó a cabo el estudio descriptivo e inferencial de las variables estudiadas. Resultado: el 64,77% de los alumnos de cuarto año de secundaria pertenecían a colegios estatales mientras que el 35,23% provenían
de colegios privados. El 46,33% de los estudiantes de cuarto de secundaria fueron varones mientras que el 53,67% fueron mujeres. Conclusiones: se ha encontrado que el instrumento creado es válido y confiable. Se encontraron diferencias estadísticamente significativas en el nivel de comprensión lectora entre los alumnos de colegios estatales y no estatales. Se han elaborado baremos diferenciados para cada tipo de colegio
Adenosine A2A receptor modulation of hippocampal CA3-CA1 synapse plasticity during associative learning in behaving mice
© 2009 Nature Publishing Group All rights reservedPrevious in vitro studies have characterized the electrophysiological and molecular signaling pathways of adenosine tonic modulation on long-lasting synaptic plasticity events, particularly for hippocampal long-term potentiation(LTP). However, it remains to be elucidated
whether the long-term changes produced by endogenous adenosine in the efficiency of synapses are related to those required for
learning and memory formation. Our goal was to understand how endogenous activation of adenosine excitatory A2A receptors modulates the associative learning evolution in conscious behaving mice. We have studied here the effects of the application of a highly selective A2A receptor antagonist, SCH58261, upon a well-known associative learning paradigm - classical eyeblink conditioning. We used a trace paradigm, with a tone as the conditioned stimulus (CS) and an electric shock presented to the supraorbital nerve as the unconditioned stimulus(US). A single electrical pulse was presented to the Schaffer collateral–commissural pathway to evoke field EPSPs (fEPSPs) in the pyramidal CA1 area during the CS–US interval. In vehicle-injected animals, there was a progressive increase in the percentage of conditioning responses (CRs) and in the slope of fEPSPs through conditioning sessions, an effect that was completely prevented (and lost) in SCH58261 (0.5 mg/kg, i.p.)-injected animals. Moreover, experimentally evoked LTP was impaired in SCH58261- injected mice. In conclusion, the endogenous activation of adenosine A2A receptors plays a pivotal effect on the associative learning process and its relevant hippocampal circuits, including activity-dependent changes at the CA3-CA1 synapse.This study was supported by grants from the Spanish Ministry of Education and Research (BFU2005-01024 and BFU2005-02512), Spanish Junta de Andalucía (BIO-122 and CVI-02487), and the Fundación Conocimiento y Cultura of
the Pablo de Olavide University (Seville, Spain).B. Fontinha was in receipt of a studentship from a project grant (POCI/SAU-NEU/56332/2004) supported by Fundação para a Ciência e Tecnologia (FCT, Portugal), and of an STSM from Cost B30 concerted action of the EU
The influence of semantic and phonological factors on syntactic decisions: An event-related brain potential study
During language production and comprehension, information about a word's syntactic properties is sometimes needed. While the decision about the grammatical gender of a word requires access to syntactic knowledge, it has also been hypothesized that semantic (i.e., biological gender) or phonological information (i.e., sound regularities) may influence this decision. Event-related potentials (ERPs) were measured while native speakers of German processed written words that were or were not semantically and/or phonologically marked for gender. Behavioral and ERP results showed that participants were faster in making a gender decision when words were semantically and/or phonologically gender marked than when this was not the case, although the phonological effects were less clear. In conclusion, our data provide evidence that even though participants performed a grammatical gender decision, this task can be influenced by semantic and phonological factors
Commissioning of the BRIKEN detector for the measurement of very exotic β-delayed neutron emitters
A new detection system has been installed at the RIKEN Nishina Center (Japan) to investigate decay properties of very neutron-rich nuclei. The setup consists of three main parts: a moderated neutron counter, a detection system sensitive to the implantation and decay of radioactive ions, and γ-ray detectors. We describe here the setup, the commissioning experiment and some selected results demonstrating its performance for the measurement of half-lives and β-delayed neutron emission probabilities. The methodology followed in the analysis of the data is described in detail. Particular emphasis is placed on the correction of the accidental neutron background
The impact from survey depth and resolution on the morphological classification of galaxies
We consistently analyse for the first time the impact of survey depth and spatial resolution on the most used morphological parameters for classifying galaxies through non-parametric methods: Abraham and Conselice-Bershady concentration indices, Gini, M20moment of light, asymmetry, and smoothness. Three different non-local data sets are used, Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) and Subaru/XMMNewton Deep Survey (SXDS, examples of deep ground-based surveys), and Cosmos Evolution Survey (COSMOS, deep space-based survey). We used a sample of 3000 local, visually classified galaxies, measuring their morphological parameters at their real redshifts (z ~ 0). Then we simulated them to match the redshift and magnitude distributions of galaxies in the non-local surveys. The comparisons of the two sets allow us to put constraints on the use of each parameter for morphological classification and evaluate the effectiveness of the commonly used morphological diagnostic diagrams. All analysed parameters suffer from biases related to spatial resolution and depth, the impact of the former being much stronger. When including asymmetry and smoothness in classification diagrams, the noise effects must be taken into account carefully, especially for ground-based surveys. M20 is significantly affected, changing both the shape and range of its distribution at all brightness levels. We suggest that diagnostic diagrams based on 2-3 parameters should be avoided when classifying galaxies in ground-based surveys, independently of their brightness; for COSMOS they should be avoided for galaxies fainter than F814 = 23.0. These results can be applied directly to surveys similar to ALHAMBRA, SXDS and COSMOS, and also can serve as an upper/lower limit for shallower/deeper ones.MP acknowledge financial support from JAE-Doc programme of the Spanish National Research Council (CSIC), co-funded by the European Social Fund. This research was supported by the Junta de Andalucia through project TIC114, and the Spanish Ministry of Economy and Competitiveness (MINECO) through projects AYA2010-15169, AYA2013-42227-P, and AYA2013-43188-P.Peer Reviewe
Strong one-neutron emission from two-neutron unbound states in β decays of the r -process nuclei Ga 86,87
β-delayed one-neutron and two-neutron branching ratios (P1n and P2n) have been measured in the decay of A=84 to 87 Ga isotopes at the Radioactive-Isotope Beam Factory (RIBF) at the RIKEN Nishina Center using a high-efficiency array of He3 neutron counters (BRIKEN). Two-neutron emission was observed in the decay of Ga84,85,87 for the first time and the branching ratios were measured to be P2n=1.6(2)%,1.3(2)%, and 10.2(28)stat(5)sys%, respectively. One-neutron branching ratio of Ga87(P1n=81(9)stat(8)sys%) and half-life of 29(4) ms were measured for the first time. The branching ratios of Ga86 were also measured to be P1n=74(2)stat(8)sys% and 16.2(9)stat(6)sys% with better precision than a previous study. The observation that P1n>P2n for both Ga86,87 was unexpected and is interpreted as a signature of dominating one-neutron emission from the two-neutron unbound excited states in Ge86,87. In order to interpret the experimental results, shell-model and Hauser-Feshbach statistical model calculations of delayed particle and γ-ray emission probabilities were performed. This model framework reproduces the experimental results. The shell model alone predicts P2n significantly larger than P1n for the Ga87 decay, and it is necessary to invoke a statistical description to successfully explain the observation that P1n>P2n. Our new results demonstrate the relevance and importance of a statistical description of neutron emission for the prediction of the decay properties of multineutron emitters and that it must be included in the r-process modeling
Research misconduct in the fields of ethics and philosophy: researchers’ perceptions in Spain
This is the Author’s Original Manuscript (AOM) (also called a “preprint”) sent to review to Science and Engineering Ethics on 11/10/2020. The final version of the article was published online at SEE on 21/01/2021. The online version is available at: https://doi.org/10.1007/s11948-021-00278-wEmpirical studies have revealed a disturbing prevalence of research misconduct in a wide variety of disciplines, although not, to date, in the areas of ethics and philosophy. This study aims to provide empirical evidence on perceptions of how serious a problem research misconduct is in these two disciplines in Spain, particularly regarding the effects that the model used to evaluate academics’ research performance may have on their ethical behaviour. The methodological triangulation applied in the study combines a questionnaire, a debate at the annual meeting of scientific association, and in-depth interviews. Of the 541 questionnaires sent out, 201 responses were obtained (37.1% of the total sample), with a significant difference in the participation of researchers in philosophy (30.5%) and in ethics (52.8%); 26 researchers took part in the debate and 14 interviews were conducted. The questionnaire results reveal that 91.5% of the respondents considered research misconduct to be on the rise; 63.2% considered at least three of the fraudulent practices referred to in the study to be commonplace, and 84.1% identified two or more such practices. The researchers perceived a high prevalence of duplicate publication (66.5%) and self-plagiarism (59.0%), use of personal influence (57.5%) and citation manipulation (44.0%), in contrast to a low perceived incidence of data falsification or fabrication (10.0%). The debate and the interviews corroborated these data. Researchers associated the spread of these misconducts with the research evaluation model applied in Spain
The impact from survey depth and resolution on the morphological classification of galaxies
We consistently analyse for the first time the impact of survey depth and spatial resolution on the most used morphological parameters for classifying galaxies through non-parametric methods: Abraham and Conselice-Bershady concentration indices, Gini, M20moment of light, asymmetry, and smoothness. Three different non-local data sets are used, Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) and Subaru/XMMNewton Deep Survey (SXDS, examples of deep ground-based surveys), and Cosmos Evolution Survey (COSMOS, deep space-based survey). We used a sample of 3000 local, visually classified galaxies, measuring their morphological parameters at their real redshifts (z ~ 0). Then we simulated them to match the redshift and magnitude distributions of galaxies in the non-local surveys. The comparisons of the two sets allow us to put constraints on the use of each parameter for morphological classification and evaluate the effectiveness of the commonly used morphological diagnostic diagrams. All analysed parameters suffer from biases related to spatial resolution and depth, the impact of the former being much stronger. When including asymmetry and smoothness in classification diagrams, the noise effects must be taken into account carefully, especially for ground-based surveys. M20 is significantly affected, changing both the shape and range of its distribution at all brightness levels. We suggest that diagnostic diagrams based on 2-3 parameters should be avoided when classifying galaxies in ground-based surveys, independently of their brightness; for COSMOS they should be avoided for galaxies fainter than F814 = 23.0. These results can be applied directly to surveys similar to ALHAMBRA, SXDS and COSMOS, and also can serve as an upper/lower limit for shallower/deeper ones.Ministerio de Economía y Competitividad AYA2010-15169, AYA2013-42227-P, AYA2013-4318
The ALHAMBRA survey: reliable morphological catalogue of 22 051 early- and late-type galaxies
Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) is photometric survey designed to trace the cosmic evolution and cosmic variance. It covers a large area of ~4 deg2 in eight fields, where seven fields overlap with other surveys, allowing us to have complementary data in other wavelengths. All observations were carried out in 20 continuous, medium band (30 nm width) optical and 3 near-infrared (JHK) bands, providing the precise measurements of photometric redshifts. In addition, morphological classification of galaxies is crucial for any kind of galaxy formation and cosmic evolution studies, providing the information about star formation histories, their environment and interactions, internal perturbations, etc. We present a morphological classification of >40 000 galaxies in the ALHAMBRA survey. We associate to every galaxy a probability to be early type using the automated Bayesian code GALSVM. Despite of the spatial resolution of theALHAMBRAimages (~1 arcsec), for 22 051 galaxies, we obtained the contamination by other type of less than 10 per cent. Of those, 1640 and 10 322 galaxies are classified as early-(down to redshifts ~0.5) and late-type (down to redshifts ~1.0), respectively, with magnitudes F613W ≤ 22.0. In addition, for magnitude range 22.0 < F613W ≤ 23.0, we classified other 10 089 late-type galaxies with redshifts ≤1.3.We show that the classified objects populate the expected regions in the colour-mass and colour-magnitude planes. The presented data set is especially attractive given the homogeneous multiwavelength coverage available in the ALHAMBRA fields, and is intended to be used in a variety of scientific applications. The low-contamination catalogue (<10 per cent) is made publicly available with this paper. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.This research was supported by the Junta de Andalucía through projects PO8-TIC-03531 and TIC114, the Spanish Ministry of Economy and Competitiveness (MINECO) through projects AYA2006-14046, AYA2010-15169, AYA2010-22111-C03-02, AYA2011-29517-C03-01, and the Generalitat Valenciana through project GV/Prometeo 2009/064. MP acknowledges financial support from JAE-Doc program of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.Peer Reviewe
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