4,541 research outputs found
Probing the Circumnuclear Stellar Populations of Starburst Galaxies in the Near-infrared
We employ the NASA Infrared Telescope Facility's near-infrared spectrograph
SpeX at 0.8-2.4m to investigate the spatial distribution of the stellar
populations (SPs) in four well known Starburst galaxies: NGC34, NGC1614,
NGC3310 and NGC7714. We use the STARLIGHT code updated with the synthetic
simple stellar populations models computed by Maraston (2005, M05). Our main
results are that the NIR light in the nuclear surroundings of the galaxies is
dominated by young/intermediate age SPs (yr), summing from
40\% up to 100\% of the light contribution. In the nuclear aperture of
two sources (NGC1614 and NGC3310) we detected a predominant old SP component
(yr), while for NGC34 and NGC7714 the younger component
prevails. Furthermore, we found evidence of a circumnuclear star formation
ring-like structure and a secondary nucleus in NGC1614, in agreement with
previous studies. We also suggest that the merger/interaction experienced by
three of the galaxies studied, NGC1614, NGC3310 and NGC7714 can explain the
lower metallicity values derived for the young SP component of these sources.
In this scenario the fresh unprocessed metal poorer gas from the
destroyed/interacting companion galaxy is driven to the centre of the galaxies
and mixed with the central region gas, before star formation takes place. In
order to deepen our analysis, we performed the same procedure of SP synthesis
using Maraston (2011, M11) EPS models. Our results show that the newer and
higher resolution M11 models tend to enhance the old/intermediate age SP
contribution over the younger ages
Least action description of dynamic pairing correlations in the fission of Curium and Californium isotopes based on the Gogny energy density functional
The impact of dynamic pairing correlations and their interplay with Coulomb
antipairing effects on the systematic of the spontaneous fission half-lives for
the nuclei Cm and Cf is analyzed, using a hierarchy of
approximations based on the parametrization D1M of the Gogny energy density
functional (EDF). First, the constrained Hartree-Fock-Bogoliubov (HFB)
approximation is used to compute deformed mean-field configurations, zero-point
quantum corrections and collective inertias either by using the Slater
approximation to Coulomb exchange and neglecting Coulomb antipairing or by
fully considering the exchange and pairing channels of the Coulomb interaction.
Next, the properties of the {\it{least action}} and {\it{least energy}} fission
paths are compared. In the {\it{least action}} case, pairing is identified as
the relevant degree of freedom in order to minimize the action entering the
Wentzel-Kramers-Brillouin (WKB) approximation to the tunneling probability
through the fission barrier. Irrespective of the treatment of Coulomb exchange
and antipairing, it is shown that the {\it{least action}} path obtained taking
into account the pairing degree of freedom leads to stronger pairing
correlations that significantly reduce the spontaneous fission half-lives
improving thereby the comparison with the experiment by several orders
of magnitude. It is also shown that the Coulomb antipairing effect is, to a
large extent, washed out by the {\it{least action}} procedure and therefore the
values obtained by the two different treatments of the Coulomb
exchange and pairing are of similar quality.Comment: 13 pages, 8 figure
Correlation properties of the kinematic Sunyaev-Zel'dovich effect and implications for Dark Energy
In the context of a cosmological study of the bulk flows in the Universe, we
present a detailed study of the statistical properties of the kinematic
Sunyaev-Zel'dovich (kSZ) effect. We first compute analytically the correlation
function and the power spectrum of the projected peculiar velocities of galaxy
clusters. By taking into account the spatial clustering properties of these
sources, we perform a line-of-sight computation of the {\em all-sky} kSZ power
spectrum and find that at large angular scales (), the local bulk flow
should leave a visible signature above the Poisson-like fluctuations dominant
at smaller scales, while the coupling of density and velocity fluctuations
should give much smaller contribution. We conduct an analysis of the prospects
of future high resolution CMB experiments (such as ACT and SPT) to detect the
kSZ signal and to extract cosmological information and dark energy constraints
from it. We present two complementary methods, one suitable for ``deep and
narrow'' surveys such as ACT and one suitable for ``wide and shallow'' surveys
such as SPT. Both methods can constraint the equation of state of dark energy
to about 5-10% when applied to forthcoming and future surveys, and probe
in complementary redshift ranges, which could shed some light on its time
evolution. These determinations of do not rely on the knowledge of cluster
masses, although they make minimal assumptions on cluster physics.Comment: 17 pages, 11 figures, submitted to ApJ, comments welcome. See
parallel work of S.DeDeo, D.N.Spergel and H.Trak (ApJ, to be submitted
Management dilemma; a woman with cystic fibrosis and severe lung disease presenting with colonic carcinoma: a case report
Introduction
There are increasing reports of bowel cancer in cystic fibrosis, suggesting a possible causal link. Individuals with cystic fibrosis who have advanced lung disease present a high operative risk, limiting curative treatment options in early bowel malignancy.
Case presentation
We describe a 41-year-old Caucasian woman with cystic fibrosis and severe lung disease who had been considered for lung transplantation, who presented with rectal bleeding and was found to have a Stage I adenocarcinoma of the sigmoid colon. After considerable discussion as to the operative risks, she underwent a laparoscopic resection and remains relatively well 1 year postoperatively with no recurrence.
Conclusion
We discuss the complexity of the management decisions for cystic fibrosis patients with severe lung disease and early stage colonic malignancy, particularly in the context of potential need for lung transplantation. The case demonstrates that cystic fibrosis patients with very severe lung function impairment may undergo laparoscopic abdominal surgical interventions without compromising postoperative airway clearance
J-PLUS: analysis of the intracluster light in the Coma cluster
The intracluster light (ICL) is a luminous component of galaxy clusters
composed of stars that are gravitationally bound to the cluster potential but
do not belong to the individual galaxies. Previous studies of the ICL have
shown that its formation and evolution are intimately linked to the
evolutionary stage of the cluster. Thus, the analysis of the ICL in the Coma
cluster will give insights into the main processes driving the dynamics in this
highly complex system. Using a recently developed technique, we measure the ICL
fraction in Coma at several wavelengths, using the J-PLUS unique filter system.
The combination of narrow- and broadband filters provides valuable information
on the dynamical state of the cluster, the ICL stellar types, and the
morphology of the diffuse light. We use the Chebyshev-Fourier Intracluster
Light Estimator (CICLE) to disentangle the ICL from the light of the galaxies,
and to robustly measure the ICL fraction in seven J-PLUS filters. We obtain the
ICL fraction distribution of the Coma cluster at different optical wavelengths,
which varies from , showing the highest values in the narrowband
filters J0395, J0410, and J0430. This ICL fraction excess is distinctive
pattern recently observed in dynamically active clusters (mergers), indicating
a higher amount of bluer stars in the ICL compared to the cluster galaxies.
Both the high ICL fractions and the excess in the bluer filters are indicative
of a merging state. The presence of younger/lower-metallicity stars the ICL
suggests that the main mechanism of ICL formation for the Coma cluster is the
stripping of the stars in the outskirts of infalling galaxies and, possibly,
the disruption of dwarf galaxies during past/ongoing mergers.Comment: 10 pages, 3 figures, 1 table. Accepted for publication in A&
Complex effects of inhibiting hepatic apolipoprotein B100 synthesis in humans
Mipomersen (Kynamro®) is an antisense oligonucleotide (ASO) that inhibits apolipoprotein B (apoB) synthesis; its LDL lowering effects should, therefore, result from reduced secretion of VLDL. We enrolled 17 healthy volunteers who received placebo injections weekly for 3-wks followed by mipomersen weekly for 7-9 wks. Stable isotopes were used after each treatment to determine fractional catabolic rates (FCRs) and production rates (PRs) of apoB in VLDL, IDL, and LDL, and of TG in VLDL. Mipomersen significantly reduced apoB in VLDL, IDL, and LDL associated with increases in FCRs of VLDL and LDL apoB and reductions in PRs of IDL and LDL apoB. Unexpectedly, the PRs of VLDL apoB and VLDL TG were unaffected. siRNA knockdown of apoB expression in HepG2 cells demonstrated preservation of apoB secretion across a range of apoB synthesis. Titrated ASO knockdown of apoB mRNA in chow-fed mice showed preservation of both apoB and TG secretion. In contrast, titrated ASO knockdown of apoB mRNA in high fat fed mice resulted in stepwise reductions of both apoB and TG secretion. Mipomersen lowered all apoB-lipoproteins without reducing the PR of either VLDL apoB or TG. Our first-in-human data are consistent with longstanding models of post-transcriptional and post-translational regulation of apoB secretion, and are supported by experiments with siRNA in HepG2 cells and ASO in mice. These results indicate that targeting apoB synthesis can lower levels of apoB-lipoproteins without necessarily reducing VLDL secretion, thereby reducing the risk of steatosis associated with this therapeutic strategy
INPUT DEVICE RESEARCH FOR DIGITAL PATHOLOGY. AN ERGONOMIC OUTLOOK
Introduction/ Background
Digital Pathology represents a technological innovation that introduces changes in the traditional work of pathologists. In this regard, an important issue that has not been enough emphasized is the image handling from an ergonomic point of view to avoid work-related musculoskeletal disorders (MSD).
Aims
The aim of this study was to investigate a proper input device for digital pathology.
Methods
Research was conducted in two phases: 1. Comparative study to find an optimal external controller. Eight medical students analyzed 11 input devices: keyboard (HP), conventional mouse (HP), vertical mouse (CLS), touchpad (Logitech), 3 trackballs (Logitech, Kensington Expert and Ulove), Rollermouse (Contour), Ergopointer (Märzhäuser Sensotech), gamepad (Logitech) and a touchless device (Leap-Motion), using them with the Image Viewer software (Ventana). The web-based Fitts´ law test (UC Berkeley) was used to objectify the accuracy of each device, randomly. 12 items were included in the questionnaire: comfort, technical aspects (cursor movement and objective achievement), prospects, overall satisfaction, prior experience, and others. 2. Evaluation by two experienced pathologists (MPR and ANO, 55 and 50 year-old, respectively) the best rated input device and comparison with a voice recognition system (Invox Medical Dictation) using a headset microphone (Plantronics), rating perceived workload using NASA Task Load Index with 28 whole slide images. Digital Image Hub (Leica) with a 4 MegaPixel display (Barco) was used. Data were processed with SPSS 21.0.
Results
Correlation between technical aspects of the evaluated devices and accuracy (Fitts´ law test), and comfort with overall satisfaction existed (p<0.05). The assessment concluded that vertical mouse was the best rated input device. However, it has a slightly higher perceived workload in comparison with the voice recognition system, which was the proper controller for digital pathology in this study.
Conclusion: We describe a methodology that can study and compare input devices for future workstations in digital pathology. Pathologists should be involved in this process trying to find ergonomic devices that prevent MSD. Voice recognition can function as a good handsfree device for digital pathology and could be considered in physical disability situations. Further studies using electromyography, accelerometry and 3D reconstruction analysis could provide additional ergonomic information
Physiological lentiviral vectors for the generation of improved CAR-T cells
Anti-CD19 chimeric antigen receptor (CAR)-T cells have achieved impressive outcomes for the treatment of relapsed and refractory B-lineage neoplasms. However, important limitations still remain due to severe adverse events (i.e., cytokine release syndrome and neuroinflammation) and relapse of 40%-50% of the treated patients. Most CAR-T cells are generated using retroviral vectors with strong promoters that lead to high CAR expression levels, tonic signaling, premature exhaustion, and overstimulation, reducing efficacy and increasing side effects. Here, we show that lentiviral vectors (LVs) expressing the transgene through a WAS gene promoter (AW-LVs) closely mimic the T cell receptor (TCR)/CD3 expression kinetic upon stimulation. These AW-LVs can generate improved CAR-T cells as a consequence of their moderate and TCR-like expression profile. Compared with CAR-T cells generated with human elongation factor alpha (EF1 alpha)-driven-LVs, AW-CAR-T cells exhibited lower tonic signaling, higher proportion of naive and stem cell memory T cells, less exhausted phenotype, and milder secretion of tumor necrosis factor alpha (TNF-alpha) and interferon (IFN)-gamma after efficient destruction of CD19(+) lymphoma cells, both in vitro and in vivo. Moreover, we also showed their improved efficiency using an in vitro CD19(+) pancreatic tumor model. We finally demonstrated the feasibility of large-scale manufacturing of AW-CAR-T cells in guanosine monophosphate (GMP)-like conditions. Based on these data, we propose the use of AWLVs for the generation of improved CAR-T products
Matrix representation and simulation algorithm of spiking neural P systems with structural plasticity
Abstract(#br)In this paper, we create a matrix representation for spiking neural P systems with structural plasticity (SNPSP, for short), taking inspiration from existing algorithms and representations for related variants. Using our matrix representation, we provide a simulation algorithm for SNPSP systems. We prove that the algorithm correctly simulates an SNPSP system: our representation and algorithm are able to capture the syntax and semantics of SNPSP systems, e.g. plasticity rules, dynamism in the synapse set. Analyses of the time and space complexity of our algorithm show that its implementation can benefit using parallel computers. Our representation and simulation algorithm can be useful when implementing SNPSP systems and related variants with a dynamic topology, in software or..
Chemical abundance of the LINER galaxy UGC 4805 with SDSS-IV MaNGA
Chemical abundance determinations in Low-Ionization Nuclear Line Regions (LINERs) are especially complex and uncertain because the nature of the ionizing source of this kind of object is unknown. In this work, we study the oxygen abundance in relation to the hydrogen abundance (O/H) of the gas phase of the UGC 4805 LINER nucleus. Optical spectroscopic data from the Mapping Nearby Galaxies (MaNGA) survey was employed to derive the O/H abundance of the UGC 4805 nucleus based on the extrapolation of the disk abundance gradient, on calibrations between O/H abundance and strong emission-lines for Active Galactic Nuclei (AGNs) as well as on photoionization models built with the Cloudy code, assuming gas accretion into a black hole (AGN) and post-Asymptotic Giant Branch (p-AGB) stars with different effective temperatures. We found that abundance gradient extrapolations, AGN calibrations, AGN and p-AGB photoionization models produce similar O/H values for the UGC 4805 nucleus and similar ionization parameter values. The study demonstrated that the methods used to estimate the O/H abundance using nuclear emission-line ratios produce reliable results, which are in agreement with the O/H values obtained from the independent method of galactic metallicity gradient extrapolation. Finally, the results from the WHAN diagram combined with the fact that the high excitation level of the gas has to be maintained at kpc scales, we suggest that the main ionizing source of the UGC 4805 nucleus probably has a stellar origin rather than an AGN.Instituto de Astrofísica de La Plat
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