2,647 research outputs found
Family and Internet
El desarrollo de la Humanidad nos dibuja un aumento en las capacidades de comunicación
del ser humano. Esta situación viene de la mano, fundamentalmente, del gran
avance que los nuevos medios de comunicación, caso de Internet, están experimentando.
Según las autoras, esta situación reclama un entendimiento entre la familia y
este medio (Internet), exige el establecimiento de unas líneas de comunicación que
ayude a los miembros de la familia en su crecimiento y socializaciónThe progress of Humanity shows an increase in the communication capacities of the
human being. This situation is bound to the great advance that the new media, such
as Internet, are experiencing and it claims for a new understanding between the family
and the new media. The authors think that the establisment of some communication
lines which would help the families in their growth and socialization are completely
necessary
Los videojuegos y su capacidad didáctico-formativa
Hoy las máquinas ocupan un lugar privilegiado en nuestra vida. Podemos destacar la
presencia de los videojuegos dentro de la dinámica familiar y escolar. Los videojuegos
pueden ser considerados como otra forma de enseñar, si esta se desarrolla a través de una
correcta supervisión. Esta situación demanda la intervención directa de la familia y de los
docentes como referentes socializadores de los niños de hoy, hombres del mañanaToday the machines occupy a privileged place in our life. We can emphasize the presence of
the video games within the familiar and scholastic dynamics. The video games can be
considered as other form of teaching, if this is developed through a correct supervision. This
demand situation the direct intervention of the family and of the educational as referring of
the children of today, men of the tomorrow
Integral field optical spectroscopy of a representative sample of ULIRGs: II. Two-dimensional kpc-scale extinction structure
We investigate the two-dimensional kpc-scale structure of the extinction in a
representative sample of local ULIRGs using the Halpha/Hbeta line ratio.We use
optical integral field spectroscopy obtained with the INTEGRAL instrument at
the William Herschel Telescope. Complementary optical and near-IR high angular
resolution HST images have also been used. The extinction exhibits a very
complex and patchy structure in ULIRGs on kpc scales, from basically
transparent regions to others deeply embedded in dust (Av~0.0 to Av~8.0 mag).
Nuclear extinction covers a broad range in Av from 0.6 to 6 mag, 69% of the
nuclei having Av>2.0 mag. Extinction in the external regions is substantially
lower than in the nuclei with 64% of the ULIRGs in the sample having median Av
of less than 2 mag for the entire galaxy. While post-coalescence nuclei tend to
cluster around Av values of 2 to 3 mag, pre-coalescence nuclei appear more
homogeneously distributed over the entire 0.4 mag <Av< 7.7 mag range. For the
average extinction (Av~2.0 derived for the ULIRGs of the sample, the ratio of
the de-reddened to observed SFR values is 6. The extinction-corrected,
Halpha-based SFR ranges from 10 to 300 Msun/yr. For only 28% of the cases the
de-reddened SFR is <20 Msun/yr, whereas for the observed SFR this percentage
increases to 72%. The IR-based SFR is always higher than the optical-based one,
with differences ranging from about 2 to up to 30. The nuclear observed SFR has
an average contribution to the total one of 16% for the entire sample. Once
corrected for extinction, the average value becomes 31%. Because of mostly
extinction effects, the optical (I-band) half-light radius in the sample
galaxies is on average a factor 2.3 larger than the corresponding near-IR
(H-band) value.Comment: To appear in A&
Thermal diagnostic of the Optical Window on board LISA Pathfinder
Vacuum conditions inside the LTP Gravitational Reference Sensor must comply
with rather demanding requirements. The Optical Window (OW) is an interface
which seals the vacuum enclosure and, at the same time, lets the laser beam go
through for interferometric Metrology with the test masses. The OW is a
plane-parallel plate clamped in a Titanium flange, and is considerably
sensitive to thermal and stress fluctuations. It is critical for the required
precision measurements, hence its temperature will be carefully monitored in
flight. This paper reports on the results of a series of OW characterisation
laboratory runs, intended to study its response to selected thermal signals, as
well as their fit to numerical models, and the meaning of the latter. We find
that a single pole ARMA transfer function provides a consistent approximation
to the OW response to thermal excitations, and derive a relationship with the
physical processes taking place in the OW. We also show how system noise
reduction can be accomplished by means of that transfer function.Comment: 20 pages, 14 figures; accepted for publication in Class. Quantum Gra
Line and Continuum Variability in Active Galaxies
We compared optical spectroscopic and photometric data for 18 AGN galaxies
over 2 to 3 epochs, with time intervals of typically 5 to 10 years. We used the
Multi-Object Double Spectrograph (MODS) at the Large Binocular Telescope (LBT)
and compared the spectra to data taken from the SDSS database and the
literature. We find variations in the forbidden oxygen lines as well as in the
hydrogen recombination lines of these sources. For 4 of the sources we find
that, within the calibration uncertainties, the variations in continuum and
line spectra of the sources are very small. We argue that it is mainly the
difference in black hole mass between the samples that is responsible for the
different degree of continuum variability. In addition we find that for an
otherwise constant accretion rate the total line variability (dominated by the
narrow line contributions) reverberates the continuum variability with a
dependency . Since
this dependency is prominently expressed in the narrow line emission it implies
that the luminosity dominating part of the narrow line region must be very
compact with a size of the order of at least 10 light years. A comparison to
literature data shows that these findings describe the variability
characteristics of a total of 61 broad and narrow line sources.Comment: 30 pages including the appendix, 18 figures including the appendix.
Accepted 2015 September 3. Received 2015 August 24; in original form 2015
July 3 in Monthly Notices of the Royal Astronomical Societ
Integral Field Spectroscopy based H\alpha\ sizes of local Luminous and Ultraluminous Infrared Galaxies. A Direct Comparison with high-z Massive Star Forming Galaxies
Aims. We study the analogy between local U/LIRGs and high-z massive SFGs by
comparing basic H{\alpha} structural characteristics, such as size, and
luminosity (and SFR) surface density, in an homogeneous way (i.e. same tracer
and size definition, similar physical scales). Methods. We use Integral Field
Spectroscopy based H{\alpha} emission maps for a representative sample of 54
local U/LIRGs (66 galaxies). From this initial sample we select 26 objects with
H{\alpha} luminosities (L(H{\alpha})) similar to those of massive (i.e. M\ast
\sim 10^10 M\odot or larger) SFGs at z \sim 2, and observed on similar physical
scales. Results. The sizes of the H{\alpha} emitting region in the sample of
local U/LIRGs span a large range, with r1/2(H{\alpha}) from 0.2 to 7 kpc.
However, about 2/3 of local U/LIRGs with Lir > 10^11.4 L\odot have compact
H{\alpha} emission (i.e. r1/2 < 2 kpc). The comparison sample of local U/LIRGs
also shows a higher fraction (59%) of objects with compact H{\alpha} emission
than the high-z sample (25%). This gives further support to the idea that for
this luminosity range the size of the star forming region is a distinctive
factor between local and distant galaxies of similar SF rates. However, when
using H{\alpha} as a tracer for both local and high-z samples, the differences
are smaller than the ones recently reported using a variety of other tracers.
Despite of the higher fraction of galaxies with compact H{\alpha} emission, a
sizable group (\sim 1/3) of local U/LIRGs are large (i.e. r1/2 > 2 kpc). These
are systems showing pre-coalescence merger activity and they are
indistinguishable from the massive high-z SFGs galaxies in terms of their
H{\alpha} sizes, and luminosity and SFR surface densities.Comment: Accepted for publication in A&A. (!5 pages, 7 figures, 2 tables
- …