3,579 research outputs found
Variability in Quasar Broad Absorption Line Outflows I. Trends in the Short-Term versus Long-Term Data
Broad absorption lines (BALs) in quasar spectra identify high velocity
outflows that likely exist in all quasars and could play a major role in
feedback to galaxy evolution. The variability of BALs can help us understand
the structure, evolution, and basic physical properties of the outflows. Here
we report on our first results from an ongoing BAL monitoring campaign of a
sample of 24 luminous quasars at redshifts 1.2<z<2.9, focusing on C IV 1549 BAL
variability in two different time intervals: 4 to 9 months (short-term) and 3.8
to 7.7 years (long-term) in the quasar rest-frame. We find that 39% (7/18) of
the quasars varied in the short-term, whereas 65% (15/23) varied in the
long-term, with a larger typical change in strength in the long-term data. The
variability occurs typically in only portions of the BAL troughs. The
components at higher outflow velocities are more likely to vary than those at
lower velocities, and weaker BALs are more likely to vary than stronger BALs.
The fractional change in BAL strength correlates inversely with the strength of
the BAL feature, but does not correlate with the outflow velocity. Both the
short-term and long-term data indicate the same trends. The observed behavior
is most readily understood as a result of the movement of clouds across the
continuum source. If the crossing speeds do not exceed the local Keplerian
velocity, then the observed short-term variations imply that the absorbers are
<6 pc from the central quasar.Comment: 14 pages, 7 figures, accepted for publication in MNRA
Simulador de comportamiento de enjambre con Quorum Sensing bacteriano
One of the most useful tools in the design of path-planning solutions is simulators. Thanks to them, it is possible to predict the performance of certain control strategies. In this paper, a simulator is presented that implements a swarm of automatons, which perform a wild motion in a user-selected environment. The robots will have the quality to avoid collisions with different obstacles that affect their mobility since they are equipped with proximity sensors. The interface of this simulator was designed entirely with the Qt Designer software. Successful configurations that replicate the performance of the real prototype are presented.
Una de las herramientas más útiles en el diseño de soluciones de planificación de trayectorias son los simuladores. Gracias a ellos, es posible predecir el rendimiento de determinadas estrategias de control. En este trabajo se presenta un simulador que implementa un enjambre de autómatas que realizan un movimiento salvaje en un entorno seleccionado por el usuario. Los robots tendrán la cualidad de evitar colisiones con diferentes obstáculos que afecten a su movilidad ya que están equipados con sensores de proximidad. La interfaz de este simulador se ha diseñado íntegramente con el software Qt Designer. Se presentan configuraciones exitosas que replican el desempeño del prototipo real.
 
Kinetics and crystallization path of a Fe-based metallic glass alloy
The thermal stability and the quantification of the different transformation processes involved in the overall crystallization of the Fe50Cr15Mo14C15B6 amorphous alloy were investigated by several characterization techniques. Formation of various metastable and stable phases during the devitrification process in the sequence a-Fe, ¿-Cr6Fe18Mo5, M23(C,B)6, M7C3, ¿-Fe3Mo3C and FeMo2B2 (with M = Fe, Cr, Mo), was observed by in-situ synchrotron high energy X-ray diffraction and in-situ transmission electron microscopy. By combining these techniques with differential scanning calorimetry data, the crystallization states and their temperature range of stability under continuous heating were related with the evolution of the crystallized fraction and the phase sequence as a function of temperature, revealing structural and chemical details of the different transformation mechanisms.Postprint (published version
Application of miRNA-seq in neuropsychiatry: A methodological perspective
MiRNAs are emerging as key molecules to study neuropsychiatric diseases. However, despite the large number of methodologies and software for miRNA-seq analyses, there is little supporting literature for researchers in this area. This review focuses on evaluating how miRNA-seq has been used to study neuropsychiatric diseases to date, analyzing both the main findings discovered and the bioinformatics workflows and tools used from a methodological perspective. The objective of this review is two-fold: first, to evaluate current miRNA-seq procedures used in neuropsychiatry; and second, to offer comprehensive information that can serve as a guide to new researchers in bioinformatics. After conducting a systematic search (from 2016 to June 30, 2020) of articles using miRNA-seq in neuropsychiatry, we have seen that it has already been used for different types of studies in three main categories: diagnosis, prognosis, and mechanism. We carefully analyzed the bioinformatics workflows of each study, observing a high degree of variability with respect to the tools and methods used and several methodological complexities that are identified and discussed in this reviewInstituto de Salud Carlos III | Ref. PI18/01311Ministerio de Economía y Competitividad | Ref. RYC2014-15246Xunta de Galicia | Ref. ED431C2018/55-GR
Multimodal agent interfaces and system architectures for health and fitness companions
Multimodal conversational spoken dialogues using physical and virtual agents provide a potential interface to motivate and support users in the domain of health and fitness. In this paper we present how such multimodal conversational Companions can be implemented to support their owners in various pervasive and mobile settings. In particular, we focus on different forms of multimodality and system architectures for such interfaces
Optimal subspaces in normed spaces
In this paper, we prove existence of optimal subspaces in a normed space. We give properties of diameters of a subspace, and properties of optimal subspaces and of its deviations. Characterization and uniqueness of optimal subspaces in an Hilbert space are considered.Fil: Cuenya, Hector Hugo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Departamento de Matemática; ArgentinaFil: Levis, Fabián Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Departamento de Matemática; ArgentinaFil: Lorenzo, Marcelo Daniel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Departamento de Matemática; ArgentinaFil: Rodríguez, C. N.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Departamento de Matemática; Argentin
Is having difficulty meeting the recommended physical activity guidelines associated with cognitive difficulties in US adults?
This abstract summarizes and gives a brief overview of our analytical research study on the associations of meeting physical activity guidelines and cognitive difficulties such as difficulty remembering/concentrating
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