350 research outputs found
Development of an Emergency Radio Beacon for Small Unmanned Aerial Vehicles
Emergency locator transmitters (ELTs) used to locate manned aircrafts are not well suited to find and recover small crashed unmanned aerial vehicles (UAVs). ELTs utilize an international satellite system for search and rescue (Cospas-Sarsat System), which should leverage its expensive resources to save lives as a priority. Besides, ELTs are too big and heavy to be used within small UAVs. Some of the existing solutions for this problem are based on receivers that detect signal strength, which may be a long and tedious process not suitable for user needs. Others do not have enough range or require radio license and expensive amateur radio receivers. This paper presents an emergency radio beacon specifically designed to locate small UAVs. It is triggered automatically in the event of a crash and allows finding and recovering a crashed UAV in a fast and simple way. It meets not only the required specifications of user-friendliness, size and weight of this kind of application, but also it is a high precision and low cost device. Besides, it has enough range and endurance. The experiments carried out show the operation of the proposed system
Proper motions of young stars in Chamaeleon. I. A Virtual Observatory study of spectroscopically confirmed members
(abridged) We want to provide further evidence of the origin of the proposed
stellar members of Chamaeleon and to identify interlopers from the foreground
\epsilon Cha and \eta Cha associations. To this aim, we compile lists of
spectroscopically confirmed members of Chamaeleon I and II, \epsilon Cha and
\eta Cha, and of background objects in the same line of sight. Using Virtual
Observatory tools, we cross-match these lists with the UCAC3 catalogue to get
the proper motions of the objects. In the vector point diagram, we identify the
different moving groups, and use this information to study the membership of
proposed candidate members of the associations from the literature. For those
objects with available radial velocities, we compute their Galactic space
velocities. We look for correlations between the known properties of the
objects and their proper motions. The members of the dark clouds exhibit
clearly different proper motions from those of the foreground associations and
of the background stars. The data suggest that Chamaeleon II could have
different dynamical properties from Chamaeleon I. Although the two foreground
clusters \epsilon and \eta Chamaeleontis constitute two different proper motion
groups, they have similar spatial motions, which are different from the spatial
motion of Chamaeleon I. On the other hand, the space motions of the Chamaeleon
II stars look more similar to those of the foreground clusters than to the
Chamaeleon I stars, but the numbers are low. Hence, with the available data it
is unclear to what extent the stellar populations in both clouds are physically
connected to each other. We find no correlations between the proper motions and
the properties of the objects in either of the clouds
La utilización del concepto de pH en la publicidad y su relación con las ideas que manejan los alumnos : aplicaciones en el aula
The broadcast on TV of some commercials where the value of the pH in the advertised products was presented as beneficial, prompted us to study them to analyse the ideas related with the acids and bases that they have. Here, we also seek possible coincidences with the ideas that students sustain. We also present a sequence of classroom activities to use commercials to work the concepts of pH and neutralization therein involved
Conceptos relacionados con los ácidos y las bases al nivel macroscópico: evolución histórica e ideas de los alumnos
El razonamiento causal secuencial en los equilibrios ácido-base múltiples : propuestas didácticas en el ámbito universitario
La principal dificultad que encuentran los estudiantes al acercarse a los equilibrios ácido-base múltiples es que precisan controlar varios equilibrios de forma simultánea. Una anticipación en la presentación a los estudiantes de educación secundaria de estos equilibrios induce a la utilización del razonamiento causal secuencial, por el cual se consideran los procesos no como equilibrios sino como compartimentos estanco (sin simultaneidad) y cada proceso como consecuencia del anterior y como causa del siguiente. En el presente artículo, por un lado, diagnosticamos las concepciones alternativas relacionadas con los equilibrios ácido-base múltiples (estudiantes universitarios, licenciados-opositores a la educación secundaria y libros universitarios); y por el otro, se centra en una propuesta de mejora del aprendizaje utilizando para ello la resolución de problemas y el ordenador como recurso auxiliar en esta resolución. Previamente analizamos los enunciados de los problemas que se plantean en algunos libros universitarios como punto de partida a nuestra propuesta didáctica, la cual se centra en que los estudiantes expliciten todos los equilibrios presentes en los procesos ácido-base múltiples como parte de una heurística para la resolución de los problemas y utilicen el ordenador para salvar las dificultades matemáticas primando el análisis del proceso químico.The need to control several equilibria simultaneously is the main difficulty met by students when they approach multiple acid-base equilibria. Presenting beforehand these equilibria to secondary school students encourages the use of causal sequential reasoning that takes processes not as equilibria but isolated, without simultaneity, each process being the cause of the former and causing the following. In this article, on the one hand we diagnose the alternative conceptions related to multiple acid-base equilibria. On the other hand we propose to improve learning by using problem solving and the computer as an auxiliary resource. We previously analyse the wording of the problems presented in some university textbooks as starting point to our didactic proposal, which asks the students to explain all the equilibria in multiple acid-base processes as part of a heuristic for problem solving and to use the computer to solve mathematical difficulties, giving priority to the analysis of the chemical process
Conceptos relacionados con los ácidos y las bases al nivel teórico y molecular: evolución histórica e ideas de los alumnos
Thrombospondin-1/CD47 interaction regulates Th17 and treg differentiation in psoriasis
Accumulating evidence on the role of Thrombospondin-1 (TSP-1) in the immune
response has emerged during the last years. In spite of the importance of TSP-1 not
only as anti-angiogenic factor but also as an immunomodulatory molecule, studies on
the role of TSP-1 in psoriasis have been neglected. TSP-1 and CD47 expression were
analyzed in skin samples from psoriasis patients and control subjects using RT-PCR and
immunofluorescence. Expression of these molecules was also evaluated in peripheral
blood CD4+ T cells, moDCs, and circulating primary DCs. The functional role of
TSP-1/CD47 signaling axis in psoriasis was assessed in Th17 and Treg differentiation
assays. Additionally, small interfering RNA assays specific to TSP-1 were performed
in CD4+ T cells and monocyte derived DC to specifically evaluate the function of
this protein. Lesional skin of psoriasis patients expressed lower TSP-1 and CD47
mRNA levels compared to non-lesional skin or skin from controls. Immunofluorescence
staining revealed decreased expression of CD47 in CD45+ dermal cells from psoriasis
samples compared to control subjects. Peripheral CD4+ T cells and circulating primary
DCs from psoriasis also expressed lower levels of CD47 compared to controls.
Although no significant differences were detected in TSP-1 expression in CD4+ T cells
and moDCs between patients and controls, TSP-1 expression in psoriasis patients
inversely correlated with disease activity evaluated by the Psoriasis Area and Index
Activity. Furthermore, exogenous TSP-1 inhibited Th17 differentiation and stimulated the
differentiation of CD4+ T cells toward Treg cells. Furthermore, RNA interference specific
for TSP-1 confirmed the role of this molecule as a negative regulator of T cell activation.
Because of the impact of TSP-1/CD47 signaling axis in Th17 and Treg differentiation, a
dysregulated expression of these molecules in the immune cells from psoriasis patients
may favor the exacerbated inflammatory response in this diseaseInstituto de Salud Carlos III (AES 2017): PI17/01972 to ED. Janssen; Spanish Ministry of Economy and Competitiveness (MINECO): Plan Nacional de Salud SAF2017-82886-R, Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV); Proyecto Integrado de Excelencia PIE13/00041, Instituto de Salud Carlos III to FS-M, Instituto de Salud Carlos III PI16/02166, Universidad Autónoma de Madrid-Banco Santander (grant 2017/EEUU/03), and Red Temática de Excelencia en Investigación en Hipoxia (SAF 2017-90794-REDT) to MJC. This research has been co-financed by Fondo Europeo de Desarrollo Regional (FEDER
Fluoro-sensing applied to detection and identification of hydrocarbons in inland waters. Study of the impact of different UV light sources
This paper presents the detection and identification of hydrocarbons through flu oro-sensing by developing a simple and inexpensive detector for inland water, in contrast to current systems, designed to be used for marine waters at large distances and being extremely costly. To validate the proposed system, three test-benches have been mounted, with various UV-Iight sources. Main application of this system would be detect hydrocarbons pollution in rivers, lakes or dams, which in fact, is of growing interest by administrations
La histología aplicada a revisión : la investigación dirigida mediante el uso de portafolios como base didáctica en su proceso de enseñanza/aprendizaje
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