142 research outputs found

    A modular docking mechanism for in-orbit assembly and spacecraft servicing

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    A Docking Mechanism concept is described which is suitable for use with autonomous docking systems. The central feature of using simple cylindrical handles on one side and a type of prism seating on the other is offered as a practical method of achieving a standardized structural interface without freezing continued development of the latches, either technically or commercially. The main emphasis in docking mechanism concepts is in two directions: (1) a very simple docking mechanism, involving mainly the latch mechanism to achieve a structural link; and (2) a sophisticated Docking Mechanism, where the latch mechanism is designed for nonrigid spacecraft and the achievement of very low dynamic interactions between spacecraft during the docking process

    Experiencias y comprensiones sobre violencias contra mujeres jóvenes : relatos de mujeres entre 18 y 29 años en la ciudad de Bogotá

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    La violencia contra mujeres jóvenes es una problemática social que ha incrementado en los últimos años, ya que las mujeres entre los 18 y 29 años son las víctimas más frecuentes de violencia basada en género. Para el año 2013, en Colombia el más alto número de mujeres asesinadas se encontraban entre los 15 y 29 años. Sin embargo, es notable el bajo índice de denuncia de hechos de violencia contra mujeres en esta etapa del ciclo vital. Por tanto, esta investigación indaga sobre experiencias y comprensiones relativas a las violencias contra las mujeres relatadas por mujeres jóvenes entre 18 y 29 años en la ciudad de Bogotá. Para el análisis de los relatos se acude a la perspectiva de género y a categorías como subjetividad femenina, violencia contra mujeres y ámbito público-privado. Se utiliza una metodología con enfoque cualitativo y se diseña un cuestionario con 24 preguntas que fue aplicado a 40 mujeres de todos los estratos socioeconómicos, divididas en dos rangos de edades: entre 18 y 23 años, y entre 24 y 29 años, posteriormente, se realizó un grupo focal con seis mujeres. Se identifica que los tipos de violencia psicológica, sexual y física son las que más afectan a las mujeres jóvenes. Igualmente se hace evidente que, si bien las jóvenes reconocen y son conscientes sobre situaciones y tipos de violencias en lugares públicos y privados en los que se sienten o están efectivamente en riesgo, la persistencia de roles estereotipados de género coexisten con discursos contradictorios de contenido relativamente emancipatorio respecto a condiciones históricas y culturales que configuran sus subjetividades, lo cual incide de manera negativa respecto a prácticas de autoprotección y de denuncia.Violence against young women is a social issue that has increased in the last few years, women between the ages of 18 and 29 are the most frequent victims of gender-based violence. In 2013, the highest number of murdered women in Colombia was between the ages of 15 and 29. However the report rate of these violent crimes against women at this stage of their life cycle is notably low. Therefore, this investigation is about experiences related to violence against women, described by young women between the ages of 18 and 29 in the city of Bogota. For the analysis of the stories, we resort to gender perspective and categories like feminine subjectivity, violence against women, and the public-private sector. We opted for a method with a qualitative focus and designed a questionnaire with 24 questions that was presented to 40 women of all the socioeconomic levels, divided in two age groups: between 18 and 23, and between 24 and 29, afterwards we formed a focal group of six women. We identified that the types of violence that most affects young women are psychological, sexual, and physical. Likewise, it s evident that if young women recognize and are conscious about situations and types of violence in public and private places in which they feel or are in fact at risk, the persistence of stereotypical gender roles coexist with contradictory speeches of relatively emancipatory content regarding historical and cultural conditions that configure their subjectivity, which influences them in a negative way regarding practices of autoprotection and reporting of crimes.Psicólogo (a)Pregrad

    Structural insights into regulation of nuclear receptors by ligands

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    Nuclear receptors are DNA-binding transcription factors, the transcriptional function of many of which depends on the binding of ligands, a feature that distinguishes nuclear receptors from other transcription factors. This review will summarize recent advances in our knowledge of the interaction between selected nuclear receptors and their cognate ligands

    Ecto-nucleotidasas, propiedades moleculares e impacto funcional

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    Ecto-nucleotidases hydrolyze extracellular nucleotides. Nucleotides are amongst the most ubiquitous messenger substances in the vertebrate body. Receptors for nucleotides are expressed on the surface of essentially every cell and many cells carry several types of nucleotide receptors. Several families of ecto-nucleotidases have been identified that differ in tissue distribution and functional properties. They modulate ligand availability at nucleotide and adenosine receptors. Ectonucleotidases were first identified in the 1940ies. Work of the past two decades has unraveled molecular identities and important functional properties. Using targeted gene deletion clear examples highlighting the importance of ecto-nucleotidases in nucleotide and adenosine signaling have been elaborated. These reach from the control of blood flow and angiogenesis to the modulation of immune functions and neural development. Specific ecto-nucleotidases are associated with stem cells in the adult mammalian brain, implicating a role of nucleotides and nucleosides in the control of adult neurogenesis. Ecto-nucleotidases represent important therapeutic targets to interfere with P2 or P1 receptor-mediated receptor signaling pathways. The development of high throughput assays promises a considerable acceleration in the development of subtype-specific ecto-nucleotidase inhibitors.Las ecto-nucleotidasas hidrolizan los nucleótidos extracelulares. Los nucleótidos se encuentran entre las sustancias mensajeras más ubicuas en vertebrados. Los receptores de nucleótidos se expresan en la superficie de prácticamente todas las células y muchas células expresan varios tipos de estos receptores. Se han identificado varias familias de ecto-nucleotidasas, las cuales difieren en su distribución tisular y en sus propiedades funcionales. Modulan la disponibilidad del ligando en los receptores de nucleótidos y de adenosina. Las ecto-nucleotidasas fueron identificadas por primera vez en la década de 1940. Los trabajos de las dos últimas décadas han mostrado sus características moleculares así como importantes propiedades funcionales. Utilizando delecciones génicas dirigidas se han mostrado claros ejemplos destacables de la importancia de las ecto-nucleotidasas en la señalización por nucléotidos y adenosina. Estos ejemplos abarcan desde el control del flujo sanguíneo y la angiogénesis a la modulación de las funciones inmunes y el desarrollo nervioso. Ecto-nucleotidasas específicas están asociadas con células madre en el cerebro adulto de mamífero, implicando un papel de los nucleótidos y nucleósidos en el control de la neurogénesis adulta. Las ecto-nucleotidasas representan importantes dianas terapéuticas para interferir en las vías de señalización mediadas por receptores P2 o P1. El desarrollo de ensayos de alto rendimiento promete una considerable aceleración en el desarrollo de inhibidores de subtipos específicos de ecto-nucleotidasas

    Revisiting mortality deceleration patterns in a gamma-Gompertz-Makeham framework

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    We calculate life-table aging rates (LARs) for overall mortality by estimating a gamma-Gompertz-Makeham (G GM) model and taking advantage of LAR’s parametric representation by Vaupel and Zhang [34]. For selected HMD countries, we study how the evolution of estimated LAR patterns could explain observed 1) longevity dynamics, and 2) mortality improvement or deterioration at different ages. Surprisingly, the age of mortality deceleration x showed almost no correlation with a number of longevity measures apart from e0. In addition, as mortality concentrates at older ages with time, its characteristic bell-shaped pattern becomes more pronounced. Moreover, in a GGM framework, we identify the impact of senescent mortality on shape of the rate of population aging. We also find evidence for a strong relationship between x and the statistically significant curvilinear changes in the evolution of e0 over time. Finally, model-based LARs appear to be consistent with point b) of the “heterogeneity hypothesis” [12]: mortality deceleration, due to selection effects, should shift to older ages as the level of total adult mortality declines

    A multilab study of bilingual infants: Exploring the preference for infant-directed speech

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    From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the multi-lab ManyBabies project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants’ preference for North-American English IDS (cf. ManyBabies Consortium, in press (MB1)), tested in 17 labs in 7 countries. Those infants were tested in two age groups: 6–9 months (the younger sample) and 12–15 months (the older sample). We found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to NAE was associated with a stronger IDS preference, extending the previous finding from MB1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments

    Quantifying Sources of Variability in Infancy Research Using the Infant-Directed-Speech Preference

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    Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure

    Quantifying sources of variability in infancy research using the infant-directed-speech preference

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    Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure. (This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 798658.
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