786 research outputs found
The Bulgeless Seyfert/LINER Galaxy NGC 3367: Disk, Bar, Lopsidedness and Environment
NGC3367 is a nearby isolated active galaxy that shows a radio jet, a strong
bar and evidence of lopsidedness. We present a quantitative analysis of the
stellar and gaseous structure of the galaxy disk and a search for evidence of
recent interaction based on new UBVRI Halpha and JHK images and on archival
Halpha Fabry-Perot and HI VLA data. From a coupled 1D/2D GALFIT bulge/bar/disk
decomposition an (B/D ~ 0.07-0.1) exponential pseudobulge is inferred in all
the observed bands. A NIR estimate of the bar strength = 0.44
places NGC 3367 bar among the strongest ones. The asymmetry properties were
studied using (1) optical and NIR CAS indexes (2) the stellar (NIR) and gaseous
(Halpha, HI) A_1 Fourier mode amplitudes and (3) the HI integrated profile and
HI mean intensity distribution. While the average stellar component shows
asymmetry values close to the average found in the Local Universe for isolated
galaxies, the young stellar component and gas values are largely decoupled
showing significantly larger A_1 mode amplitudes suggesting that the gas has
been recently perturbed. Our search for (1) faint stellar structures in the
outer regions (up to u_R ~ 26 mag arcsec^{-2}), (2) (Halpha) star-forming
satellite galaxies and (3) regions with different colors (stellar populations)
along the disk all failed. Such an absence is interpreted using recent
numerical simulations to constrain a tidal event with an LMC like galaxy to
some dynamical times in the past or to a current very low mass, gas rich
accretion. We conclude that a cold accretion mode (gas and small/dark galaxies)
may be responsible of the nuclear activity and peculiar (young stars and gas)
morphology regardless of the highly isolated environment. Black hole growth in
bulgeless galaxies may be triggered by cosmic smooth mass accretion.Comment: 27 pages, 12 figures, accepted for publication in The Astronomical
Journa
Health Promotion for Childhood Obesity: An Approach Based on Self-Tracking of Data
[EN]At present, obesity and overweight are a global health epidemic. Traditional interventions
for promoting healthy habits do not appear to be e ective. However, emerging technological solutions
based on wearables and mobile devices can be useful in promoting healthy habits. These applications
generate a considerable amount of tracked activity data. Consequently, our approach is based on
the quantified-self model for recommending healthy activities. Gamification can also be used as
a mechanism to enhance personalization, increasing user motivation. This paper describes the
quantified-self model and its data sources, the activity recommender system, and the PROVITAO
App user experience model. Furthermore, it presents the results of a gamified program applied for
three years in children with obesity and the process of evaluating the quantified-self model with
experts. Positive outcomes were obtained in children’s medical parameters and health habits
Laser Calibration System for Time of Flight Scintillator Arrays
A laser calibration system was developed for monitoring and calibrating time
of flight (TOF) scintillating detector arrays. The system includes setups for
both small- and large-scale scintillator arrays. Following test-bench
characterization, the laser system was recently commissioned in experimental
Hall B at the Thomas Jefferson National Accelerator Facility for use on the new
Backward Angle Neutron Detector (BAND) scintillator array. The system
successfully provided time walk corrections, absolute time calibration, and TOF
drift correction for the scintillators in BAND. This showcases the general
applicability of the system for use on high-precision TOF detectors.Comment: 11 pages, 11 figure
Involvement of the subthalamic nucleus in impulse control disorders associated with Parkinson’s disease
Behavioural abnormalities such as impulse control disorders may develop when patients with Parkinson’s disease receive
dopaminergic therapy, although they can be controlled by deep brain stimulation of the subthalamic nucleus. We have recorded
local field potentials in the subthalamic nucleus of 28 patients with surgically implanted subthalamic electrodes. According to
the predominant clinical features of each patient, their Parkinson’s disease was associated with impulse control disorders
(n = 10), dyskinesias (n = 9) or no dopaminergic mediated motor or behavioural complications (n = 9). Recordings were obtained
during the OFF and ON dopaminergic states and the power spectrum of the subthalamic activity as well as the subthalamocortical
coherence were analysed using Fourier transform-based techniques. The position of each electrode contact was determined
in the postoperative magnetic resonance image to define the topography of the oscillatory activity recorded in each
patient. In the OFF state, the three groups of patients had similar oscillatory activity. By contrast, in the ON state, the patients
with impulse control disorders displayed theta-alpha (4–10 Hz) activity (mean peak: 6.71 Hz) that was generated 2–8mm below
the intercommissural line. Similarly, the patients with dyskinesia showed theta-alpha activity that peaked at a higher frequency
(mean: 8.38 Hz) and was generated 0–2mm below the intercommissural line. No such activity was detected in patients that
displayed no dopaminergic side effects. Cortico-subthalamic coherence was more frequent in the impulsive patients in the
4–7.5 Hz range in scalp electrodes placed on the frontal regions anterior to the primary motor cortex, while in patients with
dyskinesia it was in the 7.5–10 Hz range in the leads overlying the primary motor and supplementary motor area. Thus,
dopaminergic side effects in Parkinson’s disease are associated with oscillatory activity in the theta-alpha band, but at different
frequencies and with different topography for the motor (dyskinesias) and behavioural (abnormal impulsivity) manifestations.
These findings suggest that the activity recorded in parkinsonian patients with impulse control disorders stems from the
associative-limbic area (ventral subthalamic area), which is coherent with premotor frontal cortical activity. Conversely, in
patients with L-dopa-induced dyskinesias such activity is recorded in the motor area (dorsal subthalamic area) and it is coherent
with cortical motor activity. Consequently, the subthalamic nucleus appears to be implicated in the motor and behavioural
complications associated with dopaminergic drugs in Parkinson’s disease, specifically engaging different anatomo-functional
territories
The hologram and its utilization as a physics teaching tool for physics teaching in engineering courses
With the emergence and development of the white-light holograms, new possibilities were created for its utilization as a teaching tool due to the characteristic of producing a three-dimensional image which constitutes an optical duplicate of the object. In this work the distinctive aspects of the hologram are described and its utilization is analyzed in engineering courses, through the design and construction of a Didactic Exhibition of Holography.Con el surgimiento de los hologramas reconstruibles con luz blanca y su desarrollo posterior, se abrieron grandes posibilidades para su utilizaciĂłn como medio de enseñanza por la caracterĂstica de producir una imagen tridimensional que constituye un duplicado Ăłptico de un objeto. En el trabajo se describen las caracterĂsticas distintivas del holograma como un medio de enseñanza de la fĂsica y se analiza su utilizaciĂłn en carreras de ingenierĂa, mediante la fundamentaciĂłn, el diseño y construcciĂłn de una ExposiciĂłn Didáctica de HolografĂa creada para este propĂłsito.1401.11401.1
The impact of silent vascular brain burden in cognitive impairment in Parkinson's disease
White matter hyperintensities (WMHs) detected by magnetic
resonance imaging (MRI) of the brain are associated with dementia and cognitive
impairment in the general population and in Alzheimer's disease. Their effect in
cognitive decline and dementia associated with Parkinson's disease (PD) is still
unclear. METHODS: We studied the relationship between WMHs and cognitive state in
111 patients with PD classified as cognitively normal (n = 39), with a mild
cognitive impairment (MCI) (n = 46) or dementia (n = 26), in a cross-sectional
and follow-up study. Cognitive state was evaluated with a comprehensive
neuropsychological battery, and WMHs were identified in FLAIR and T2-weighted
MRI. The burden of WMHs was rated using the Scheltens scale. RESULTS: No
differences in WMHs were found between the three groups in the cross-sectional
study. A negative correlation was observed between semantic fluency and the
subscore for WMHs in the frontal lobe. Of the 36 non-demented patients
re-evaluated after a mean follow-up of 30 months, three patients converted into
MCI and 5 into dementia. Progression of periventricular WMHs was associated with
an increased conversion to dementia. A marginal association between the increase
in total WMHs burden and worsening in the Mini Mental State Examination was
encountered. CONCLUSIONS: White matter hyperintensities do not influence the
cognitive status of patients with PD. Frontal WMHs have a negative impact on
semantic fluency. Brain vascular burden may have an effect on cognitive
impairment in patients with PD as WMHs increase overtime might increase the risk
of conversion to dementia. This finding needs further confirmation in larger
prospective studies
Isospin structure of one- and two-phonon GDR excitations
Isospin is included in the description of Coulomb excitation of multiple
giant isovector dipole resonances. In the excitation of even-even nuclei, a
relevant portion of the excitation strength is shown to be associated with 1+
two-phonon states, which tends to be hindered or completely supressed in
calculations in which the isospin degree of freedom is not considered. We find
that the excitation cross sections is strongly dependent on the ground state
isospin.Comment: 8 pages, 2 figure
The unprecedented optical outburst of the quasar 3C 454.3. The WEBT campaign of 2004-2005
The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting
more than 1 year and culminating in spring 2005. The maximum brightness
detected was R = 12.0, which represents the most luminous quasar state thus far
observed (M_B ~ -31.4). In order to follow the emission behaviour of the source
in detail, a large multiwavelength campaign was organized by the Whole Earth
Blazar Telescope (WEBT). Continuous optical, near-IR and radio monitoring was
performed in several bands. ToO pointings by the Chandra and INTEGRAL
satellites provided additional information at high energies in May 2005. The
historical radio and optical light curves show different behaviours. Until
about 2001.0 only moderate variability was present in the optical regime, while
prominent and long-lasting radio outbursts were visible at the various radio
frequencies, with higher-frequency variations preceding the lower-frequency
ones. After that date, the optical activity increased and the radio flux is
less variable. This suggests that the optical and radio emissions come from two
separate and misaligned jet regions, with the inner optical one acquiring a
smaller viewing angle during the 2004-2005 outburst. Moreover, the colour-index
behaviour (generally redder-when-brighter) during the outburst suggests the
presence of a luminous accretion disc. A huge mm outburst followed the optical
one, peaking in June-July 2005. The high-frequency (37-43 GHz) radio flux
started to increase in early 2005 and reached a maximum at the end of our
observing period (end of September 2005). VLBA observations at 43 GHz during
the summer confirm theComment: 7 pages, 4 figures, to be published in A&
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