5,199 research outputs found
Weak Lensing Peaks in Simulated Light-Cones: Investigating the Coupling between Dark Matter and Dark Energy
In this paper, we study the statistical properties of weak lensing peaks in
light-cones generated from cosmological simulations. In order to assess the
prospects of such observable as a cosmological probe, we consider simulations
that include interacting Dark Energy (hereafter DE) models with coupling term
between DE and Dark Matter. Cosmological models that produce a larger
population of massive clusters have more numerous high signal-to-noise peaks;
among models with comparable numbers of clusters those with more concentrated
haloes produce more peaks. The most extreme model under investigation shows a
difference in peak counts of about with respect to the reference
CDM model. We find that peak statistics can be used to
distinguish a coupling DE model from a reference one with the same power
spectrum normalisation. The differences in the expansion history and the growth
rate of structure formation are reflected in their halo counts, non-linear
scale features and, through them, in the properties of the lensing peaks. For a
source redshift distribution consistent with the expectations of future
space-based wide field surveys, we find that typically seventy percent of the
cluster population contributes to weak-lensing peaks with signal-to-noise
ratios larger than two, and that the fraction of clusters in peaks approaches
one-hundred percent for haloes with redshift z0.5. Our analysis
demonstrates that peak statistics are an important tool for disentangling DE
models by accurately tracing the structure formation processes as a function of
the cosmic time.Comment: accepted in MNRAS, figures improved and text update
Explicit computation of second-order moments of importance sampling estimators for fractional Brownian motion
We study a family of importance sampling estimators of the probability of level crossing when the crossing level is large or the intensity of the noise is small. We develop a method which gives, explicitly the asymptotics of the second-order moment. Some of the results apply to fractional Brownian motion, some are more general. The main tools are refined versions of classical large-deviations results
Pemenuhan Hak-hak Pendidikan Keagamaan Islam Anak Binaan di Lembaga Pemasyarakatan Pakjo Palembang
Latar belakang pemilihan judul ini didasarkan pada kajian empiris dan teoritis, bahwa pembinaan yang diberikan bagi Anak Binaan sudah selayaknya harus di perhatiakan dengan baik. Anak merupakan generasi penerus bangsa oleh karena itu, anak harus diberikan kasih sayang agar anak dapat tumbuh dan berkembang dengan baik. Seorang anak yang tidak mendapat kasih sayang, ia akan cenderung menjadi anak yang nakal dan akibatnya dapat melakukan perbuatan yang menyimpang yang melanggar undang-undang. Anak yang demikian harus menjalani proses pidana yang berujung pada suatu pembinaan yang terjadi di Lembaga Pemasyarakatan Anak. Salah satu bentuk pembinaan yang ada di Lembaga Pemasyarakatan Anak adalah pembinaan yang bersumber pada individu anak. Pembinaan itu disebut dengan pembinaan anak secara perorangan (individual treatment).Metode penelitian yang digunakan adalah deskriptif kualitatif. Penelitian deskriptif kualitatif bertujuan untuk menganggkat fakta, keadaan dan fenomena yang terjadi ketika penelitian berlangsung dan menyajikan data apa adanya.Pelaksanaan dalam pemenuhan hak-hak pendidikan keagamaan Islam juga tidak terlepas dari kendala yang ada, baik itu struktur, substansi, dan kultur. Pada struktur, pembinaan anak perorangan memerlukan kuantitas dan kualitas dari tenaga pembina yang berhadapan langsung dengan anak didik. Pada substansi, peraturan Perundang-undangan mengenai anak mengakibatkan timbulnya stigma yang membekas pada diri anak. Pada kultur, sangat dibutuhkan peran pihak di luar Lembaga Pemasyarakatan Anak (LPA), yaitu keluarga dan masyarakat.Dari ketiga kelemahan tersebut hanya menekankan pada kesejahteraan anak mendorong munculnya pembinaan restoratif. Pembinaan secara restoratif dilakukan dengan melibatkan pihak-pihak yang ada disekitarnya, yaitu pelaku, keluarga, masyarakat, dan tidak tertutup kemungkinan korban sehingga membina anak dilakukan secara lebih manusiawi karena juga tetap diperhatikan kepentingan lainnya, yaitu masyarakat dan korban.Hal lain yang mendukung keberhasilan pembinaan anak didik pemasyarakatan adalah adanya partisispasi dari orang tua, keluarga, dan masyarakat. Dengan memperhatikan dan bersikap mau menerima anak tersebut, maka program pembinaan yang dilaksanakan di Lembaga Pemasyarakatan Anak (LPA) akan berjalan dengan baik dan berhasil
The HST view of the innermost narrow line region
We analyze the properties of the innermost narrow line region in a sample of
low-luminosity AGN. We select 33 LINERs (bona fide AGN) and Seyfert galaxies
from the optical spectroscopic Palomar survey observed by HST/STIS. We find
that in LINERs the [NII] and [OI] lines are broader than the [SII] line and
that the [NII]/[SII] flux ratio increases when moving from ground-based to HST
spectra. This effect is more pronounced considering the wings of the lines. Our
interpretation is that, as a result of superior HST spatial resolution, we
isolate a compact region of dense ionized gas in LINERs, located at a typical
distance of about 3 pc and with a gas density of about 10-10 cm,
which we identify with the outer portion of the intermediate line region (ILR).
Instead, we do not observe these kinds of effects in Seyferts; this may be the
result of a stronger dilution from the NLR emission, since the HST slit maps a
larger region in these sources. Alternatively, we argue that the innermost,
higher density component of the ILR is only present in Seyferts, while it is
truncated at larger radii because of the presence of the circumnuclear torus.
The ILR is only visible in its entirety in LINERs because the obscuring torus
is not present in these sources.Comment: 11 pages, 9 figures, A&A in pres
HST emission-line images of nearby 3CR radio galaxies: two photoionization, accretion and feedback modes
We present HST/ACS narrow-band images of a low-z sample of 19 3C radio
galaxies to study the H and [OIII] emissions from the narrow-line
region (NLR). Based on nuclear emission line ratios, we divide the sample into
High and Low Excitation Galaxies (HEGs and LEGs). We observe different line
morphologies, extended line emission on kpc scale, large [OIII]/H
scatter across the galaxies, and a radio-line alignment. In general, HEGs show
more prominent emission line properties than LEGs: larger, more disturbed, more
luminous, and more massive regions of ionized gas with slightly larger covering
factors. We find evidence of correlations between line luminosities and (radio
and X-ray) nuclear luminosities. All these results point to a main common
origin, the active nucleus, which ionize the surrounding gas. However, the
contribution of additional photoionization mechanism (jet shocks and star
formation) are needed to account for the different line properties of the two
classes. A relationship between the accretion, photoionization and feedback
modes emerges from this study. For LEGs (hot-gas accretors), the synchrotron
emission from the jet represents the main source of ionizing photons. The lack
of cold gas and star formation in their hosts accounts for the moderate
ionized-gas masses and sizes. For HEGs (cold-gas accretors), an ionizing
continuum from a standard disk and shocks from the powerful jets are the main
sources of photoionization, with the contribution from star formation. These
components, combined with the large reservoir of cold/dust gas brought from a
recent merger, account for the properties of their extended emission-line
regions.Comment: accepted for publication on ApJ (22 pages, 12 figures
Compressed correlation functions and fast aging dynamics in metallic glasses
We present x-ray photon correlation spectroscopy measurements of the atomic
dynamics in a Zr67Ni33 metallic glass, well below its glass transition
temperature. We find that the decay of the density fluctuations can be well
described by compressed, thus faster than exponential, correlation functions
which can be modeled by the well-known Kohlrausch-Williams-Watts function with
a shape exponent {\beta} larger than one. This parameter is furthermore found
to be independent of both waiting time and wave-vector, leading to the
possibility to rescale all the correlation functions to a single master curve.
The dynamics in the glassy state is additionally characterized by different
aging regimes which persist in the deep glassy state. These features seem to be
universal in metallic glasses and suggest a non diffusive nature of the
dynamics. This universality is supported by the possibility of describing the
fast increase of the structural relaxation time with waiting time using a
unique model function, independently of the microscopic details of the system.Comment: 7 pages, 4 figures. To be published in J. Chem. Phy
Spectral Energy Distributions of low-luminosity radio galaxies at z~1-3: a high-z view of the host/AGN connection
We study the Spectral Energy Distributions, SEDs, (from FUV to MIR bands) of
the first sizeable sample of 34 low-luminosity radio galaxies at high
redshifts, selected in the COSMOS field. To model the SEDs we use two different
template-fitting techniques: i) the Hyperz code that only considers single
stellar templates and ii) our own developed technique 2SPD that also includes
the contribution from a young stellar population and dust emission. The
resulting photometric redshifts range from z ~0.7 to 3 and are in substantial
agreement with measurements from earlier work, but significantly more accurate.
The SED of most objects is consistent with a dominant contribution from an old
stellar population with an age ~1 - 3 10^{9} years. The inferred total stellar
mass range is ~10^{10} - 10^{12} M(sun). Dust emission is needed to account for
the 24micron emission in 15 objects. Estimates of the dust luminosity yield
values in the range L_{dust} ~10^{43.5} -10^{45.5} erg s^{-1}. The global dust
temperature, crudely estimated for the sources with a MIR excess, is ~ 300-850
K. A UV excess is often observed with a luminosity in the range ~
10^{42}-10^{44} erg s^{-1} at 2000 A rest frame.
Our results show that the hosts of these high-z low-luminosity radio sources
are old massive galaxies, similarly to the local FRIs. However, the UV and MIR
excesses indicate the possible significant contribution from star formation
and/or nuclear activity in such bands, not seen in low-z FRIs. Our sources
display a wide variety of properties: from possible quasars at the highest
luminosities, to low-luminosity old galaxies.Comment: 28 pages, 15 figures, Accepted for publication in the Astrophysical
Journa
Mg/Ti multilayers: structural, optical and hydrogen absorption properties
Mg-Ti alloys have uncommon optical and hydrogen absorbing properties,
originating from a "spinodal-like" microstructure with a small degree of
chemical short-range order in the atoms distribution. In the present study we
artificially engineer short-range order by depositing Pd-capped Mg/Ti
multilayers with different periodicities and characterize them both
structurally and optically. Notwithstanding the large lattice parameter
mismatch between Mg and Ti, the as-deposited metallic multilayers show good
structural coherence. Upon exposure to H2 gas a two-step hydrogenation process
occurs, with the Ti layers forming the hydride before Mg. From in-situ
measurements of the bilayer thickness L at different hydrogen pressures, we
observe large out-of-plane expansions of the Mg and Ti layers upon
hydrogenation, indicating strong plastic deformations in the films and a
consequent shortening of the coherence length. Upon unloading at room
temperature in air, hydrogen atoms remain trapped in the Ti layers due to
kinetic constraints. Such loading/unloading sequence can be explained in terms
of the different thermodynamic properties of hydrogen in Mg and Ti, as shown by
diffusion calculations on a model multilayered systems. Absorption isotherms
measured by hydrogenography can be interpreted as a result of the elastic
clamping arising from strongly bonded Mg/Pd and broken Mg/Ti interfaces
Predicting Secondary Structures, Contact Numbers, and Residue-wise Contact Orders of Native Protein Structure from Amino Acid Sequence by Critical Random Networks
Prediction of one-dimensional protein structures such as secondary structures
and contact numbers is useful for the three-dimensional structure prediction
and important for the understanding of sequence-structure relationship. Here we
present a new machine-learning method, critical random networks (CRNs), for
predicting one-dimensional structures, and apply it, with position-specific
scoring matrices, to the prediction of secondary structures (SS), contact
numbers (CN), and residue-wise contact orders (RWCO). The present method
achieves, on average, accuracy of 77.8% for SS, correlation coefficients
of 0.726 and 0.601 for CN and RWCO, respectively. The accuracy of the SS
prediction is comparable to other state-of-the-art methods, and that of the CN
prediction is a significant improvement over previous methods. We give a
detailed formulation of critical random networks-based prediction scheme, and
examine the context-dependence of prediction accuracies. In order to study the
nonlinear and multi-body effects, we compare the CRNs-based method with a
purely linear method based on position-specific scoring matrices. Although not
superior to the CRNs-based method, the surprisingly good accuracy achieved by
the linear method highlights the difficulty in extracting structural features
of higher order from amino acid sequence beyond that provided by the
position-specific scoring matrices.Comment: 20 pages, 1 figure, 5 tables; minor revision; accepted for
publication in BIOPHYSIC
The MURALES survey II. Presentation of MUSE observations of 20 3C low-z radio galaxies and first results
We present observations of a complete sub-sample of 20 radio galaxies from
the Third Cambridge Catalog (3C) with redshift <0.3 obtained from VLT/MUSE
optical integral field spectrograph. These data have been obtained as part of
the survey MURALES (a MUse RAdio Loud Emission line Snapshot survey) with the
main goal of exploring the Active Galactic Nuclei (AGN) feedback process in a
sizeable sample of the most powerful radio sources at low redshift. We present
the data analysis and, for each source, the resulting emission line images and
the 2D gas velocity field. Thanks to their unprecedented depth (the median 3
sigma surface brightness limit in the emission line maps is 6X10^-18 erg s-1
cm-2 arcsec-2, these observations reveal emission line structures extending to
several tens of kiloparsec in most objects. In nine sources the gas velocity
shows ordered rotation, but in the other cases it is highly complex. 3C sources
show a connection between radio morphology and emission line properties.
Whereas, in three of the four Fanaroff and Riley Class I radio galaxies (FRIs),
the line emission regions are compact, ~1 kpc in size; in all but one of the
Class II radiogalaxies FRIIs, we detected large scale structures of ionized gas
with a median extent of 17 kpc. Among the FRIIs, those of high and low
excitation show extended gas structures with similar morphological properties,
suggesting that they both inhabit regions characterized by a rich gaseous
environment on kpc scale.Comment: Accepted for publication in A&
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