236,567 research outputs found
Unveiling the Meaning of Social Justice in Colombia
English Abstract: Through the presentation of the history of social justice in global constitutional discourse, this article aims to demonstrate that, although in Colombia there is not a constitutionalized purpose or principle of social justice, as in other countries, the modern notion of distributive justice, also called social justice today, is implicit in the Constitution of 1991 because it enshrined as mandatory rules the three main elements of its meaning at the time of its promulgation: the principle of social rule of law, the principle of human dignity and the right to a material equality. Thus, in Colombia social justice must not be understood in the Aristotelian sense of distributive justice but in accordance with these three elements, and can only be achieved if they are fulfilled.
Spanish Abstract: Mediante la presentación de la historia de la justicia social en el discurso constitucional global, este artículo pretende demostrar que, a pesar de no existir en Colombia, como en otros países, un valor o principio constitucional de justicia social, la noción moderna de justicia distributiva, también llamada hoy justicia social, se encuentra implícita en la Constitución de 1991 porque esta consagró como normas obligatorias los tres elementos principales de su significado en el tiempo en el que fue promulgada: el principio de Estado Social de Derecho, el principio de dignidad humana y el derecho a una igualdad material. Así pues, la justicia social debe entenderse en Colombia a partir de esos tres elementos, no según el sentido aristotélico de justicia distributiva, y sólo puede ser alcanzada si ellos se cumplen
Sixteen years of X-ray monitoring of Sagittarius A*: Evidence for a decay of the faint flaring rate from 2013 August, 13 months before a rise in the bright flaring rate
Recently, in a study the X-ray flaring activity of Sgr A* with Chandra and
XMM-Newton public observations from 1999 to 2014 and 2014 Swift data, it has
been argued that the "bright and very bright" flaring rate raised from 2014
Aug. 31. Thanks to 482ks of observations performed in 2015 with Chandra,
XMM-Newton and Swift, we test the significance of this rise of flaring rate and
determine the threshold of unabsorbed flare flux or fluence leading to any
flaring-rate change. The mean unabsorbed fluxes of the 107 flares detected in
the 1999-2015 observations are consistently computed from the extracted spectra
and calibration files, assuming the same spectral parameters. We construct the
observed flare fluxes and durations distribution for the XMM-Newton and Chandra
flares and correct it from the detection biases to estimate the intrinsic
distribution from which we determine the average flare detection efficiency for
each observation. We apply the BB algorithm on the flare arrival times
corrected from the corresponding efficiency. We confirm a constant overall
flaring rate in 1999-2015 and a rise in the flaring rate for the most
luminous/energetic flares from 2014 Aug. 31 (4 months after the passage of the
DSO/G2 close to Sgr A*). We also identify a decay of the flaring rate for the
less luminous and less energetic flares from 2013 Aug. and Nov., respectively
(10 and 7 months before the pericenter of the DSO/G2). The decay of the faint
flaring rate is difficult to explain by the tidal disruption of the DSO/G2,
whose stellar nature is now well established, since it occurred well before its
pericenter. Moreover, a mass transfer from the DSO/G2 to Sgr A* is not required
to produce the rise in the bright flaring rate since the energy saved by the
decay of the number of faint flares during a long time period may be later
released by several bright flares during a shorter time period. (abridged)Comment: Accepted in A&A in 2017 April 2
Time- and spatially-resolved magnetization dynamics driven by spin-orbit torques
Current-induced spin-orbit torques (SOTs) represent one of the most effective
ways to manipulate the magnetization in spintronic devices. The orthogonal
torque-magnetization geometry, the strong damping, and the large domain wall
velocities inherent to materials with strong spin-orbit coupling make SOTs
especially appealing for fast switching applications in nonvolatile memory and
logic units. So far, however, the timescale and evolution of the magnetization
during the switching process have remained undetected. Here, we report the
direct observation of SOT-driven magnetization dynamics in Pt/Co/AlO dots
during current pulse injection. Time-resolved x-ray images with 25 nm spatial
and 100 ps temporal resolution reveal that switching is achieved within the
duration of a sub-ns current pulse by the fast nucleation of an inverted domain
at the edge of the dot and propagation of a tilted domain wall across the dot.
The nucleation point is deterministic and alternates between the four dot
quadrants depending on the sign of the magnetization, current, and external
field. Our measurements reveal how the magnetic symmetry is broken by the
concerted action of both damping-like and field-like SOT and show that
reproducible switching events can be obtained for over reversal
cycles
The Complete Calibration of the Color-Redshift Relation (C3R2) Survey: Survey Overview and Data Release 1
A key goal of the Stage IV dark energy experiments Euclid, LSST and WFIRST is
to measure the growth of structure with cosmic time from weak lensing analysis
over large regions of the sky. Weak lensing cosmology will be challenging: in
addition to highly accurate galaxy shape measurements, statistically robust and
accurate photometric redshift (photo-z) estimates for billions of faint
galaxies will be needed in order to reconstruct the three-dimensional matter
distribution. Here we present an overview of and initial results from the
Complete Calibration of the Color-Redshift Relation (C3R2) survey, designed
specifically to calibrate the empirical galaxy color-redshift relation to the
Euclid depth. These redshifts will also be important for the calibrations of
LSST and WFIRST. The C3R2 survey is obtaining multiplexed observations with
Keck (DEIMOS, LRIS, and MOSFIRE), the Gran Telescopio Canarias (GTC; OSIRIS),
and the Very Large Telescope (VLT; FORS2 and KMOS) of a targeted sample of
galaxies most important for the redshift calibration. We focus spectroscopic
efforts on under-sampled regions of galaxy color space identified in previous
work in order to minimize the number of spectroscopic redshifts needed to map
the color-redshift relation to the required accuracy. Here we present the C3R2
survey strategy and initial results, including the 1283 high confidence
redshifts obtained in the 2016A semester and released as Data Release 1.Comment: Accepted to ApJ. 11 pages, 5 figures. Redshifts can be found at
http://c3r2.ipac.caltech.edu/c3r2_DR1_mrt.tx
Joint Hybrid Precoder and Combiner Design for mmWave Spatial Multiplexing Transmission
Millimeter-wave (mmWave) communications have been considered as a key
technology for future 5G wireless networks because of the orders-of-magnitude
wider bandwidth than current cellular bands. In this paper, we consider the
problem of codebook-based joint analog-digital hybrid precoder and combiner
design for spatial multiplexing transmission in a mmWave multiple-input
multiple-output (MIMO) system. We propose to jointly select analog precoder and
combiner pair for each data stream successively aiming at maximizing the
channel gain while suppressing the interference between different data streams.
After all analog precoder/combiner pairs have been determined, we can obtain
the effective baseband channel. Then, the digital precoder and combiner are
computed based on the obtained effective baseband channel to further mitigate
the interference and maximize the sum-rate. Simulation results demonstrate that
our proposed algorithm exhibits prominent advantages in combating interference
between different data streams and offer satisfactory performance improvement
compared to the existing codebook-based hybrid beamforming schemes
Cosmological Horizons, Uncertainty Principle and Maximum Length Quantum Mechanics
The cosmological particle horizon is the maximum measurable length in the
Universe. The existence of such a maximum observable length scale implies a
modification of the quantum uncertainty principle. Thus due to non-locality of
quantum mechanics, the global properties of the Universe could produce a
signature on the behaviour of local quantum systems. A Generalized Uncertainty
Principle (GUP) that is consistent with the existence of such a maximum
observable length scale is where ( is the Hubble parameter and is the
speed of light). In addition to the existence of a maximum measurable length
, this form of GUP implies also the existence
of a minimum measurable momentum . Using appropriate representation of the position and momentum
quantum operators we show that the spectrum of the one dimensional harmonic
oscillator becomes where
is the dimensionless properly
normalized energy level, is a dimensionless parameter
with and for
(we show the full form of in the text). For a typical
vibrating diatomic molecule and we find and therefore for such a system, this effect is beyond reach of
current experiments. However, this effect could be more important in the early
universe and could produce signatures in the primordial perturbation spectrum
induced by quantum fluctuations of the inflaton field.Comment: 11 pages, 7 Figures. The Mathematica file that was used for the
production of the Figures may be downloaded from
http://leandros.physics.uoi.gr/maxlenqm
Is "Better Data" Better than "Better Data Miners"? (On the Benefits of Tuning SMOTE for Defect Prediction)
We report and fix an important systematic error in prior studies that ranked
classifiers for software analytics. Those studies did not (a) assess
classifiers on multiple criteria and they did not (b) study how variations in
the data affect the results. Hence, this paper applies (a) multi-criteria tests
while (b) fixing the weaker regions of the training data (using SMOTUNED, which
is a self-tuning version of SMOTE). This approach leads to dramatically large
increases in software defect predictions. When applied in a 5*5
cross-validation study for 3,681 JAVA classes (containing over a million lines
of code) from open source systems, SMOTUNED increased AUC and recall by 60% and
20% respectively. These improvements are independent of the classifier used to
predict for quality. Same kind of pattern (improvement) was observed when a
comparative analysis of SMOTE and SMOTUNED was done against the most recent
class imbalance technique. In conclusion, for software analytic tasks like
defect prediction, (1) data pre-processing can be more important than
classifier choice, (2) ranking studies are incomplete without such
pre-processing, and (3) SMOTUNED is a promising candidate for pre-processing.Comment: 10 pages + 2 references. Accepted to International Conference of
Software Engineering (ICSE), 201
Discussion on "Sparse graphs using exchangeable random measures" by F. Caron and E. B. Fox
Discussion on "Sparse graphs using exchangeable random measures" by F. Caron
and E. B. Fox. In this discussion we contribute to the analysis of the GGP
model as compared to the Erdos-Renyi (ER) and the preferential attachment (AB)
models, using different measures such as number of connected components, global
clustering coefficient, assortativity coefficient and share of nodes in the
core.Comment: 2 pages, 1 figur
Protocol for soil functionality assessment in vineyards
Protocols used by Resolve partners during the project, to assess soil functionality on degraded aeras and evaluate soil restoration after applying recovering practices
Interchange reconnection associated with a confined filament eruption: Implications for the source of transient cold-dense plasma in solar winds
The cold-dense plasma is occasionally detected in the solar wind with in situ
data, but the source of the cold-dense plasma remains illusive. Interchange
reconnections (IRs) between closed fields and nearby open fields are well known
to contribute to the formation of solar winds. We present a confined filament
eruption associated with a puff-like coronal mass ejection (CME) on 2014
December 24. The filament underwent successive activations and finally erupted,
due to continuous magnetic flux cancellations and emergences. The confined
erupting filament showed a clear untwist motion, and most of the filament
material fell back. During the eruption, some tiny blobs escaped from the
confined filament body, along newly-formed open field lines rooted around the
south end of the filament, and some bright plasma flowed from the north end of
the filament to remote sites at nearby open fields. The newly-formed open field
lines shifted southward with multiple branches. The puff-like CME also showed
multiple bright fronts and a clear southward shift. All the results indicate an
intermittent IR existed between closed fields of the confined erupting filament
and nearby open fields, which released a portion of filament material (blobs)
to form the puff-like CME. We suggest that the IR provides a possible source of
cold-dense plasma in the solar wind
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