5,340 research outputs found

    On Neuromechanical Approaches for the Study of Biological Grasp and Manipulation

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    Biological and robotic grasp and manipulation are undeniably similar at the level of mechanical task performance. However, their underlying fundamental biological vs. engineering mechanisms are, by definition, dramatically different and can even be antithetical. Even our approach to each is diametrically opposite: inductive science for the study of biological systems vs. engineering synthesis for the design and construction of robotic systems. The past 20 years have seen several conceptual advances in both fields and the quest to unify them. Chief among them is the reluctant recognition that their underlying fundamental mechanisms may actually share limited common ground, while exhibiting many fundamental differences. This recognition is particularly liberating because it allows us to resolve and move beyond multiple paradoxes and contradictions that arose from the initial reasonable assumption of a large common ground. Here, we begin by introducing the perspective of neuromechanics, which emphasizes that real-world behavior emerges from the intimate interactions among the physical structure of the system, the mechanical requirements of a task, the feasible neural control actions to produce it, and the ability of the neuromuscular system to adapt through interactions with the environment. This allows us to articulate a succinct overview of a few salient conceptual paradoxes and contradictions regarding under-determined vs. over-determined mechanics, under- vs. over-actuated control, prescribed vs. emergent function, learning vs. implementation vs. adaptation, prescriptive vs. descriptive synergies, and optimal vs. habitual performance. We conclude by presenting open questions and suggesting directions for future research. We hope this frank assessment of the state-of-the-art will encourage and guide these communities to continue to interact and make progress in these important areas

    Death, sex, and fertility: female infanticide in rural Spain, 1750-1950

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    Relying on longitudinal micro data from rural Spain between 1750 and 1950, this article evidences that families mortally neglected a significant fraction of their female babies. Firstly, baptism records exhibited exceptionally high sex ratios at birth until the late nineteenth century. Secondly, having no previous male siblings increased the probability of male baptisms. Likewise, this same feature, together with the number of siblings alive, also increased female mortality during the first day of life. These findings are concentrated at higher parities and among landless and semi-landless families. Lastly, under-registration cannot explain these patterns affecting female mortality shortly after birth

    The effect of height on family formation in rural Spain, birth-cohorts 1835-1975

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    This article examines the relationship between the height of adult males and marital outcomes, including likelihood of marrying, age at marriage, and marital fertility, in rural Spain. For this analysis, a sample of 4, 501 men born between 1835 and 1975 living in 14 villages in northeastern Spain was taken. Previous research has shown that shorter individuals are less likely to marry. However, it is still disputed whether differences exist in the timing of marrying based on height, and little attention has been paid to the effect(s) of height on offspring. Family data were obtained from parish records and interviews with individuals and their families, while height data were obtained from military records, with individuals in Spain being conscripted at the age of 21 years. The data were linked according to nominative criteria using family reconstitution methods. The results confirm that shorter individuals were less likely to marry. Individuals of medium and medium-high height were the first to marry, with a small gap between them and shorter individuals. With regard to marital fertility, no difference in terms of average fertility by height were found, but there were small differences in timing of childbirth, possibly as a result of delayed marriage

    Analytical Modeling of Interference Aware Power Control for the Uplink of Heterogeneous Cellular Networks

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    Inter-cell interference is one of the main limiting factors in current Heterogeneous Cellular Networks (HCNs). Uplink Fractional Power Control (FPC) is a well known method that aims to cope with such limiting factor as well as to save battery live. In order to do that, the path losses associated with Mobile Terminal (MT) transmissions are partially compensated so that a lower interference is leaked towards neighboring cells. Classical FPC techniques only consider a set of parameters that depends on the own MT transmission, like desired received power at the Base Station (BS) or the path loss between the MT and its serving BS, among others. Contrary to classical FPC, in this paper we use stochastic geometry to analyze a power control mechanism that keeps the interference generated by each MT under a given threshold. We also consider a maximum transmitted power and a partial compensation of the path loss. Interestingly, our analysis reveals that such Interference Aware (IA) method can reduce the average power consumption and increase the average spectral efficiency. Additionally, the variance of the interference is reduced, thus improving the performance of Adaptive Modulation and Coding (AMC) since the interference can be better estimated at the MT.Comment: 13 pages, 1 table and 7 figures. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Height and political activism in rural Aragón (Spain) during the 20th century. A new perspective using individual-level data

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    This article explores the relationship between the political leanings of more than 1000 men born in the 1870–1970 s in 11 rural Aragonese villages and their biological well-being during childhood and adolescence, proxied by height. The aim is to test whether an individual was more likely to be left-wing if his level of biological well-being was lower and, therefore, with more incentives to fight against the social inequality that had negatively affected his family. Our results confirm that, for most of the study period, there was a strong relationship between shorter height and political activism1 in left-wing parties and organizations

    A Survey of Meteoric Activity over Spain during the Eighth Fifteenth Centuries

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    The lack of astronomical observations from medieval and early modern Spanish sources is a constant in the records of solar eclipses, meteors, and other celestial phenomena. This may be partially explained by the absence of a documentary corpus similar to the Monumenta Germaniae Historica, for example, that scholars may use for conducting a systematic search of such records; the problems increase by the presence of four different vernacular languages in the peninsula: Castilian, Catalan, Basque, and Galician, together with some other minority languages, to which Latin and Arabic must be added for historical research purposes. Currently, scientific literature records few medieval Spanish astronomical accounts, and most of them are contained in wider Arab surveys or they come from the best-known annals and chronicles. Our article intends to fill this gap partially in the issue of meteoritic activity. We present a survey of meteors, bolides, and meteor storms observed in Spain in the eighth-fourteenth centuries. Most of them have not been previously published and come from local or minor sources, but for the sake of completeness, we have included some records already mentioned by other authors.A part of this work was supported by grant P1.1B2012-47 from Universitat Jaume I.Martínez Uso, MJ.; Marco Castillo, FJ. (2016). A Survey of Meteoric Activity over Spain during the Eighth Fifteenth Centuries. Journal for the History of Astronomy. 47:168-193. https://doi.org/10.1177/0021828616649316S1681934

    Fifteenth Century Comets in Non-Astronomical Catalan Manuscripts

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    [EN] From the fifteenth century onwards, it was common in Western Europe to consider astrology as the best instrument to provide a link between the circumstances of life on the Earth and the disposition of the stars in the universe. The intimate relation between astronomy and astrology is reflected even in non-specialist works where the words astrònom and astròleg are used indistinctly. To this effect, the intrusion of astrology into medicine is also revealing, mainly in the countries of the Mediterranean and Western Europe, where several university chairs in both astronomy and astrology were established.Martínez Uso, MJ.; Marco Castillo, FJ. (2016). Fifteenth Century Comets in Non-Astronomical Catalan Manuscripts. Journal of Catalan Studies. (18/19):51-65. http://hdl.handle.net/10251/136514S516518/1

    Breaking the misery wheel? Fertility control, social mobility, and biological well-being in rural Spain (1835–1959)

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    Abstract Fertility control strategies became widespread in rural Spain through the twentieth century: a significant number of parents decided to reduce their marital fertility once the advantages of control strategies became widely known. This paper explores the impact of those practices on children through a comparative study of the heights and occupations of grandparents, parents, and children. We analyze more than 1,200 individuals from three different generations born between 1835 and 1959 in 14 rural Spanish villages, studying whether the advantages associated with fertility control were maintained over time favoring a better family status or whether they were diluted in the next generation. The largest increases in height were among children whose parents controlled their fertility by stopping having children before the mother's 36th birthday. However, it does not seem that this increase in biological well-being was accompanied by major episodes of upward social mobility

    Occultation of Planets by the Moon in European Narrative Medieval Sources

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    [EN] Existing research dealing with astronomical observations from medieval Europe have extensively covered topics such as solar and lunar eclipses and sightings of comets and meteors, but no compilation of occultations of planets by the Moon has been carried out and, till now, the data have remained scattered in different publications. The main reasons for this are the small number of observations that has reached us, their limited use for calculation of parameters associated with the rotation of the Earth, and the fact that between the fifth and fifteenth centuries, the period that we consider, almost none of these observations were made scientifically, since they usually appear in narrative texts, be they chronicles or annals. Our purpose is to make a compilation of these phenomena, trying to shed light on some of the most controversial observations after examining them in their historical context. We will examine European sources, but, occasionally, we will also consider reports from other parts of the world to make comparisons, when necessary.This paper was partially supported by the UJI-B2016-18, 16I356 project. The authors would like to thank the anonymous reviewers for their helpful and constructive comments that greatly contributed to improving the final version of the paper. They would also like to thank the editor for generous comments and support during the review process.Martínez Uso, MJ.; Marco Castillo, FJ. (2019). Occultation of Planets by the Moon in European Narrative Medieval Sources. Journal for the History of Astronomy. 50(2):192-220. https://doi.org/10.1177/0021828619845950S19222050
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