2,329 research outputs found
Analysis of Moon impact flashes detected during the 2012 and 2013 Perseids
We present the results of our Moon impact flashes detection campaigns
performed around the maximum activity period of the Perseid meteor shower in
2012 and 2013. Just one flash produced by a Perseid meteoroid was detected in
2012 because of very unfavourable geometric conditions, but 12 of these were
confirmed in 2013. The visual magnitude of the flashes ranged between 6.6 and
9.3. A luminous efficiency of 1.8 10 has been estimated for
meteoroids from this stream. According to this value, impactor masses would
range between 1.9 and 190 g. In addition, we propose a criterion to establish,
from a statistical point of view, the likely origin of impact flashes recorded
on the lunar surface.Comment: Accepted for publication in Astronomy and Astrophysics on March 11,
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Frecuencia de comportamientos anormales y estereotipados en caballos de patrullaje policial urbano : estudio de 48 horas continuas
ABSTRACT: Abnormal and stereotypic behaviors in horses have been widely studied around the world and different epidemiological situations have been described for behavioral disturbances. Objective: To determine the frequency of abnormal and stereotypic behaviors in a population of police patrolling horses. Additionally, to establish chronic stress levels in the population of interest. Methods: Twenty police horses were evaluated. The animals went through 48 hours of continuous observation to record the frequency of normal, abnormal, and stereotypic behaviors. Cortisol index (CI) was calculated for all the subjects. Results: A 65% of the horses expressed behavioral disturbances, with 55% corresponding to stereotypies. The abnormal behaviors consisted on wood chewing, pawing, and bed eating. Stereotypic behaviors were weaving, stall walking, and aerophagia (crib-biting or wind sucking). According to the CI, 13 horses were under chronic stress (CI<0.30). Conclusion: High level of chronic stress, expressed as abnormal and stereotypic behaviors, was observed in the horses.RESUMEN: los comportamientos anormales y estereotipados en caballos han sido ampliamente
estudiados en el mundo, así como también diversas situaciones epidemiológicas relacionadas con estos
disturbios. Objetivo: determinar la frecuencia de los comportamientos anormales y estereotipados en una
población de caballos de patrullaje de la policía y establecer su nivel de estrés crónico. Métodos: se evaluaron
20 caballos. Los animales fueron observados durante 48 horas continuas para recopilar los comportamientos
anormales y estereotipados. El índice del cortisol (CI) fue calculado para todos los animales. Resultados:
el 65% de la población estudiada expresó disturbios del comportamiento, y el 55% de dichos disturbios se
clasificó como estereotipias. Los comportamientos anormales observados consistieron en lignofagia, patear
y comer cama. Los comportamientos estereotipados fueron balanceo, caminar en círculos y aerofagia. El CI
mostró presencia de estrés crónico en 13 caballos (CI<0.30). Conclusión: se encontró un alto porcentaje de
estrés crónico en los caballos de la policía, expresado como comportamientos anormales y estereotipados
The Northern χ -Orionid meteoroid stream and possible association with the potentially hazardous asteroid 2008XM1
We present new orbital data and dynamic results pointing towards the origin of the Northern χ -Orionid meteoroid stream, which is a part of the Taurid meteoroid complex. A new software package was developed to establish the potential parent bodies of meteoroid streams based on the similarity of their orbits. The analysis of a Northern χ -Orionid fireball observed on 2011 December 6 identified two potential parent bodies: the near-Earth object (NEO) 2002XM35 (previously proposed as the parent of this meteoroid stream) and the more recently discovered potentially hazardous asteroid 2008XM1. The calculation of the evolution of the orbital elements performed by using the Mercury 6 symplectic integrator supports the idea
that 2008XM1 is a better parent body. Our data sample was expanded by including also in the calculations the mean orbit of the χ -Orionid stream. The results are consistent with the fragmentation of a larger body in the past that could give rise to both NEOs and the Northern χ -Orionid stream. To confirm this, further observations to improve the orbital elements of these asteroids should be attempted before the objects are lost. The analysis of the emission spectrum recorded for this fireball supports a primitive nature for these meteoroids.Ministerio de Ciencia e Innovación AYA2009-13227, AYA2009-14000-C03- 01, AYA2011-26522CSIC 201050I043Junta de Andalucía P09-FQM-455
Effect of the microstructure generated by repetitive corrugation and straightening (RCS) process on the mechanical properties and stress corrosion cracking of Al-7075 alloy
This study discussed the effect of the heterogeneous microstructure generated through the Repetitive Corrugation and Straightening (RCS) process on the mechanical and stress corrosion cracking behavior of the AA7075. As a result of the RCS process, significant grain refinement was obtained. The average grain size ranged from 126 to 59 µm, for the initial condition and 4 RCS passes, respectively. The yield strength and hardness increased 170% and 15% from the initial pass, remaining almost constant afterward. The evaluation of stress corrosion cracking showed a decrement in the number of cracks of 21.6% and 23.5% between the initial condition and fourth RCS passes. The cracking and pitting corrosion were the dominant mechanisms in the tested samples. The mechanical and corrosion results were also discussed in terms of the microstructural features.Peer ReviewedPostprint (published version
Bright fireballs associated with the potentially hazardous asteroid 2007LQ19
We analyse here two very bright fireballs produced by the ablation in the atmosphere of two large meteoroids in 2009 and 2010. These slow-moving and deep-penetrating events were observed over Spain in the framework of our Spanish Fireball Network continuous meteor monitoring campaign. The analysis of the emission spectrum imaged for one of these fireballs has provided the first clues about the chemical nature of the progenitor meteoroids. The orbital parameters of these particles suggest a likely association with the recently identified July ρ-Herculid (JRH) meteoroid stream. In addition, considerations about the likely parent body of this stream are also made on the basis of orbital dissimilarity criteria. This orbital analysis reveals that both meteoroids and PHA 2007LQ19 exhibit a similar evolution during a time period of almost 8000 years, which suggests that either this near Earth object (NEO) is the potential parent of these particles or that this NEO and both meteoroids had a common progenitor in the past.España, Ministerio de Ciencia e Innovación YA2011-26522Junta de Andalucía P09-FQM-455
On the activity of the γ -Ursae Minorids meteoroid stream in 2010 and 2011
Accurate orbital data obtained for the recently discovered γ -Ursae Minorids meteoroid stream during the 2010 and 2011 Spanish Meteor Network and Finnish Fireball Network observing ampaigns are presented. In particular, we focus on an outburst detected in 2010 and on the analysis of the first emission spectrum recorded for a member of this meteoroid stream. An array of high-sensitivity CCD video devices operating from different locations in Spain and Finland was used to perform this study. We have obtained precise trajectory, radiant and orbital information for seven members of this stream. Considerations about its likely parent body based on orbital dissimilarity criteria are made. We also present an estimation of the tensile strength for these meteoroids and a unique emission spectrum of a γ -Ursae inorid fireball that reveals that the main rocky components have chondritic abundances.Ministerio de Ciencia e Innovación AYA2009-13227, AYA2009-14000-C03-01, AYA2011-26522, AYA2011-30106-C02-01CSIC #201050I043Junta de Andalucía P09-FQM-455
On more realistic environment distributions for defining, evaluating and developing intelligence
One insightful view of the notion of intelligence is the ability
to perform well in a diverse set of tasks, problems or environments. One of
the key issues is therefore the choice of this set, which can be formalised
as a `distribution¿. Formalising and properly defining this distribution is
an important challenge to understand what intelligence is and to achieve
artificial general intelligence (AGI). In this paper, we agree with previous
criticisms that a universal distribution using a reference universal Turing
machine (UTM) over tasks, environments, etc., is perhaps amuch too general
distribution, since, e.g., the probability of other agents appearing on
the scene or having some social interaction is almost 0 for many reference
UTMs. Instead, we propose the notion of Darwin-Wallace distribution for
environments, which is inspired by biological evolution, artificial life and
evolutionary computation. However, although enlightening about where
and how intelligence should excel, this distribution has so many options
and is uncomputable in so many ways that we certainly need a more practical
alternative. We propose the use of intelligence tests over multi-agent
systems, in such a way that agents with a certified level of intelligence at
a certain degree are used to construct the tests for the next degree. This
constructive methodology can then be used as a more realistic intelligence
test and also as a testbed for developing and evaluating AGI systems.We thank the anonymous reviewers for their helpful comments. We also thank the funding from the Spanish MEC and MICINN for projects
TIN2009-06078-E/TIN, Consolider-Ingenio CSD2007-00022 and TIN2010-21062-
C02, for MEC FPU grant AP2006-02323, and Generalitat Valenciana for Prometeo/2008/051Hernández Orallo, J.; Dowe, DL.; España Cubillo, S.; Hernández-Lloreda, MV.; Insa Cabrera, J. (2011). On more realistic environment distributions for defining, evaluating and developing intelligence. En Artificial General Intelligence. Springer Verlag (Germany). 6830:82-91. https://doi.org/10.1007/978-3-642-22887-2_9S82916830Dowe, D.L.: Foreword re C. S. Wallace. Computer Journal 51(5), 523–560 (2008); Christopher Stewart WALLACE (1933-2004) memorial special issueDowe, D.L.: Minimum Message Length and statistically consistent invariant (objective?) Bayesian probabilistic inference - from (medical) “evidence”. Social Epistemology 22(4), 433–460 (2008)Dowe, D.L.: MML, hybrid Bayesian network graphical models, statistical consistency, invariance and uniqueness. In: Bandyopadhyay, P.S., Forster, M.R. (eds.) Handbook of the Philosophy of Science. Philosophy of Statistics, vol. 7, pp. 901–982. Elsevier, Amsterdam (2011)Dowe, D.L., Hajek, A.R.: A computational extension to the Turing Test. In: 4th Conf. of the Australasian Cognitive Science Society, Newcastle, Australia (1997)Goertzel, B.: The Embodied Communication Prior: A characterization of general intelligence in the context of Embodied social interaction. In: 8th IEEE International Conference on, Cognitive Informatics, ICCI 2009, pp. 38–43. IEEE, Los Alamitos (2009)Goertzel, B., Bugaj, S.V.: AGI Preschool: a framework for evaluating early-stage human-like AGIs. In: Intl. Conf. on Artificial General Intelligence (AGI 2009) (2009)Hernández-Orallo, J.: Beyond the Turing Test. J. Logic, Language & Information 9(4), 447–466 (2000)Hernández-Orallo, J.: On the computational measurement of intelligence factors. In: Meystel, A. (ed.) Performance metrics for intelligent systems workshop, pp. 1–8. National Institute of Standards and Technology, Gaithersburg (2000)Hernández-Orallo, J.: A (hopefully) non-biased universal environment class for measuring intelligence of biological and artificial systems. In: Hutter, M., et al. (eds.) Artificial General Intelligence, pp. 182–183 (2010)Hernández-Orallo, J., Dowe, D.L.: Measuring universal intelligence: Towards an anytime intelligence test. Artificial Intelligence 174(18), 1508–1539 (2010)Hernández-Orallo, J., Minaya-Collado, N.: A formal definition of intelligence based on an intensional variant of Kolmogorov complexity. In: Proc. Intl Symposium of Engineering of Intelligent Systems (EIS 1998), pp. 146–163. ICSC Press (1998)Herrmann, E., Call, J., Hernández-Lloreda, M.V., Hare, B., Tomasello, M.: Humans have evolved specialized skills of social cognition: The cultural intelligence hypothesis. Science 317(5843), 1360–1366 (2007)Hibbard, B.: Bias and No Free Lunch in Formal Measures of Intelligence. Journal of Artificial General Intelligence 1(1), 54–61 (2009)Krebs, J.R., Dawkins, R.: Animal signals: mind-reading and manipulation. Behavioural Ecology: an evolutionary approach 2, 380–402 (1984)Langton, C.G.: Artificial life: An overview. The MIT Press, Cambridge (1997)Legg, S., Hutter, M.: A collection of definitions of intelligence. In: Proc. of the 2007 Conf. on Artificial General Intelligence, pp. 17–24. IOS Press, Amsterdam (2007)Legg, S., Hutter, M.: Universal intelligence: A definition of machine intelligence. Minds and Machines 17(4), 391–444 (2007)Levin, L.A.: Universal sequential search problems. Problems of Information Transmission 9(3), 265–266 (1973)Sanghi, P., Dowe, D.L.: A computer program capable of passing IQ tests. In: Proc. 4th ICCS International Conference on Cognitive Science (ICCS 2003), Sydney, Australia, pp. 570–575 (2003)Schmidhuber, J.: A computer scientist’s view of life, the universe, and everything. In: Foundations of Computer Science, p. 201. Springer, Heidelberg (1997)Schmidhuber, J.: The Speed Prior: a new simplicity measure yielding near-optimal computable predictions. In: Kivinen, J., Sloan, R.H. (eds.) COLT 2002. LNCS (LNAI), vol. 2375, pp. 123–127. Springer, Heidelberg (2002)Solomonoff, R.J.: A formal theory of inductive inference. Part I. Information and control 7(1), 1–22 (1964)Stone, P., Veloso, M.: Towards collaborative and adversarial learning: A case study in robotic soccer. Intl. J. of Human-Computers Studies 48(1), 83–104 (1998)Tomasello, M., Herrmann, E.: Ape and human cognition: What’s the difference? Current Directions in Psychological Science 19(1), 3–8 (2010
Texture and strain rate sensitivity analysis of solid solution and precipitation hardening aluminum alloys processed by repetitive corrugation and straightening
The potential of improving the mechanical strength by the RCS process is evaluated on the 5754, 6061, and 7075 aluminum alloys, which present different hardening mechanisms related to their respective alloying elements. This work compares the evolution of the texture and the mechanical properties of the different alloys through the RCS processing. The mechanical
properties were evaluated by micro-hardness measurements, tensile tests at different temperatures, and strain rates to evaluate the strain-rate sensitivity. The results showed that after two RCS passes, the 6061 and 5754 alloys showed a relatively high strain-rate sensitivity at 300°C. In addition, an increment of 27%, 22%, 15% in hardness was obtained for the 5754, 6061 and 7075 alloys, respectively. Showing the potential of improvement in the mechanical resistance due to the
different hardening mechanism. Furthermore, the crystallographic texture was characterized by the obtention of pole figures by X-ray diffraction and the calculation of their orientation distribution functions. The results showed the same trend in the three aluminum alloys, i.e., the initial texture components were conserved, but the texturized volume decreased.Peer ReviewedPostprint (published version
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