5,978 research outputs found
Correction of D-Loop, D-Transposition of the Great Arteries and Sub-Pulmonary Stenosis with a Dacron Conduit and Stented Porcine Xenograft Valve
Total correction of transposition of the great arteries and left ventricular outflow tract obstruction has become feasible in recent years. Certain modifications are needed, however, to improve the long term function of the valved conduit required in the procedure. A stented porcine xenograft valve, sutured into a woven Dacron tubular graft, was used successfully in the total correction of such a malfunction. The patient described is the first so treated at the Henry Ford Hospital. The main advantage of this technique is its practicality. Both Dacron tubular grafts and stented porcine xenograft valves are commercially available. This approach is applicable also in the repair of congenital cardiac malformations which have discontinuity between the right ventricle and the pulmonary artery
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Stratospheric ozone depletion: a key driver of recent precipitation trends in South Eastern South America
On a hemispheric scale, it is now well established that stratospheric ozone depletion has been the principal driver of externally forced atmospheric circulation changes south of the Equator in the last decades of the 20th Century. The impact of ozone depletion has been felt over the entire hemisphere, as reflected in the poleward drift of the midlatitude jet, the southward expansion of the summertime Hadley cell and accompanying precipitation trends deep into the subtropics. On a regional scale, however, surface impacts directly attributable to ozone depletion have yet to be identified. In this paper we focus on South Eastern South America (SESA), a region that has exhibited one of the largest wetting trends during the 20th Century. We study the impact of ozone depletion on SESA precipitation using output from 6 different climate models, spanning a wide range of complexity. In all cases we contrast pairs of model integrations with and without ozone depletion, but with all other forcings identically specified. This allows for unambiguous attribution of the computed precipitation trends. All 6 climate models consistently reveal that stratospheric ozone depletion results in a significant wetting of SESA over the period 1960–1999. Taken as a whole, these model results strongly suggest that the impact of ozone depletion on SESA precipitation has been as large as, and quite possibly larger than, the one caused by increasing greenhouse gases over the same period
La Ley del Precio Unitario en la Zona Metropolitana Fronteriza
Menu prices from 8 international restaurant franchises are utilized to examine deviations from purchasing power parity between Mexico and the United States. Products in the sample are sold on both sides of the border in Ciudad Juarez, Mexico and El Paso, USA. The results indicate that Borderplex restaurant prices respond very quickly to variations in the peso/dollar exchange rate. In addition to econmetric and staitsitical evidence, graphical illustrations are also provided
La Ley del Precio Unitario en la Zona Metropolitana Fronteriza
Menu prices from 8 international restaurant franchises are utilized to examine deviations from purchasing power parity between Mexico and the United States. Products in the sample are sold on both sides of the border in Ciudad Juarez, Mexico and El Paso, USA. The results indicate that Borderplex restaurant prices respond very quickly to variations in the peso/dollar exchange rate. In addition to econmetric and staitsitical evidence, graphical illustrations are also provided
Single-Stranded Condensation Stochastically Blocks G-Quadruplex Assembly in Human Telomeric RNA
"This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jpclett.8b00722."[EN] TERRA is an RNA molecule transcribed from human subtelomeric regions toward chromosome ends potentially involved in regulation of heterochromatin stability, semiconservative replication, and telomerase inhibition, among others. TERRA contains tandem repeats of the sequence GGGUUA, with a strong tendency to fold into a four-stranded arrangement known as a parallel G-quadruplex. Here, we demonstrate by using single-molecule force spectroscopy that this potential is limited by the inherent capacity of RNA to self-associate randomly and further condense into entropically more favorable structures. We stretched RNA constructions with more than four and less than eight hexanucleotide repeats, thus unable to form several G-quadruplexes in tandem, flanked by non-G-rich overhangs of random sequence by optical tweezers on a one by one basis. We found that condensed RNA stochastically blocks G-quadruplex folding pathways with a near 20% probability, a behavior that is not found in DNA analogous molecules.Dedicated to the memory of Alfredo Villasante. The authors thank E. Poyatos-Racionero for auxiliary experiments. I.G. is supported by Fundacion IMDEA Nanociencia and M.G. by a Juan de la Cierva contract (FJCI-2016-28474). This research received grants from the MINECO (MAT2015-71806-R and BFU2017-89707-P). IMDEA Nanociencia acknowledges support from the "Severo Ochoa" Programme for Centres of Excellence in R&D (MINECO, Grant SEV-2016-0686).Gutiérrez, I.; Garavís, M.; De Lorenzo, S.; Villasante, A.; González, C.; Arias-Gonzalez, JR. (2018). Single-Stranded Condensation Stochastically Blocks G-Quadruplex Assembly in Human Telomeric RNA. The Journal of Physical Chemistry Letters. 9(10):2498-2503. https://doi.org/10.1021/acs.jpclett.8b00722S2498250391
Observational constraints to boxy/peanut bulge formation time
Boxy/peanut bulges are considered to be part of the same stellar structure as
bars and both could be linked through the buckling instability. The Milky Way
is our closest example. The goal of this letter is determining if the mass
assembly of the different components leaves an imprint in their stellar
populations allowing to estimate the time of bar formation and its evolution.
To this aim we use integral field spectroscopy to derive the stellar age
distributions, SADs, along the bar and disc of NGC 6032. The analysis shows
clearly different SADs for the different bar areas. There is an underlying old
(>=12 Gyr) stellar population for the whole galaxy. The bulge shows star
formation happening at all times. The inner bar structure shows stars of ages
older than 6 Gyrs with a deficit of younger populations. The outer bar region
presents a SAD similar to that of the disc. To interpret our results, we use a
generic numerical simulation of a barred galaxy. Thus, we constrain, for the
first time, the epoch of bar formation, the buckling instability period and the
posterior growth from disc material. We establish that the bar of NGC 6032 is
old, formed around 10 Gyr ago while the buckling phase possibly happened around
8 Gyr ago. All these results point towards bars being long-lasting even in the
presence of gas.Comment: Accepted for publication in MNRAS Letter
A two frame feedback linearization scheme for the control of fully rated wind generating units
The present paper proposes an innovative control scheme for a fully rated wind generating unit equipped with a permanent magnet synchronous generator. The main objective of this control strategy is that of allowing a decoupled and dynamically performing control of active power (by the MPPT curve) and reactive power at the point of interconnection to the grid. Moreover, the control will be able to integrate frequency supporting logics, such as synthetic inertial control and active power curtailment. The control synthesis is fully detailed and validated by means of dedicated simulations in comparison with the traditional control scheme for this type of wind generators
Integral Field Spectroscopy of the Central Regions of 3C 120: Evidence of a Past Merging Event
IFS combined with HST WFPC imaging were used to characterize the central
regions of the Seyfert 1 radio galaxy 3C 120. We carried out the analysis of
the data, deriving intensity maps of different emission lines and the continua
at different wavelengths from the observed spectra. Applying a 2D modeling to
the HST images we decoupled the nucleus and the host galaxy, and analyzed the
host morphology. The host is a highly distorted bulge dominated galaxy, rich in
substructures. We developed a new technique to model the IFS data extending the
2D modeling. Using this technique we separated the Seyfert nucleus and the host
galaxy spectra, and derived a residual data cube with spectral and spatial
information of the different structures in 3C 120. Three continuum-dominated
structures (named A, B, and C) and other three extended emission line regions
(EELRs, named E1, E2 and E3) are found in 3C 120 which does not follow the
general behavior of a bulge dominated galaxy. We also found shells in the
central kpc that may be remnants of a past merging event in this galaxy. The
origin of E1 is most probably due to the interaction of the radio-jet of 3C 120
with the intergalactic medium. Structures A, B, and the shell at the southeast
of the nucleus seem to correspond to a larger morphological clumpy structure
that may be a tidal tail, consequence of the past merging event. We found a
bright EELR (E2) in the innermost part of this tidal tail, nearby the nucleus,
which shows a high ionization level. The kinematics of the E2 region and its
connection to the tidal tail suggest that the tail has channeled gas from the
outer regions to the center.Comment: 55 pages, 18 figures and 5 tables Accepted by AP
Adverse effects of immunotherapies for multiple sclerosis: A network meta-analysis
This is the protocol for a review and there is no abstract. The objectives are as follows: To compare adverse effects of immunotherapies for people with multiple sclerosis (MS) or clinically isolated syndrome (CIS), and to rank these treatments according to their relative risks of adverse effects
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