11,467 research outputs found
Polymorphic ventricular arrhythmia triggered by temporary epicardial right ventricular stimulation after cardiac surgery
Temporary epicardial pacing is commonly used for rhythmic support in the acute postoperative period after cardiac surgery. Clinical studies suggest that pacing in the left ventricular epicardium during resynchronization therapy may be proarrhythmic in a minority of patients. The epicardial pacing increases transmural heterogeneity of repolarization. This could prolong the QT and JT intervals on the electrocardiogram (ECG), with subsequent proarrhythmic effects. The following case describes polymorphic ventricular arrhythmias after temporary epicardial ventricular stimulation
Battery Manufacturing Resource Assessment to Minimise Component Production Environmental Impacts
A promising route to attain a reliable impact reduction of supply chain materials is based on considering circular economy approaches, such as material recycling strategies. This work aimed to evaluate potential benefits of recycling scenarios for steel, copper, aluminium and plastic materials to the battery manufacturing stage. Focused on this aim, the life cycle assessment (LCA) and the environmental externalities methodologies were applied to two battery study cases: lithium manganese oxide and vanadium redox flow (VRFB) batteries, based on a cradle-to-gate LCA approach. In general, the results provided an insight into the raw material handling route. Environmental impacts were diminished by more than 20% in almost all the indicators, due to the lower consumption of virgin materials related to the implemented recyclability route. Particularly, VRFB exhibited better recyclability ratio than the Li-ion battery. For the former, the key components were the periphery ones attaining around 70% of impact reduction by recycling steel. Components of the power subsystem were also relevant, reaching around 40% of environmental impact reduction by recycling plastic. The results also foresaw opportunities for membranes, key components of VRFB materials. Based on findings, recycling strategies may improve the total circularity performance and economic viability of the studied systems
Supersymmetric QCD flavor changing top quark decay
We present a detailed and complete calculation of the gluino and scalar
quarks contribution to the flavour-changing top quark decay into a charm quark
and a photon, gluon, or a Z boson within the minimal supersymmetric standard
model including flavour changing gluino-quarks-scalar quarks couplings in the
right-handed sector. We compare the results with the ones presented in an
earlier paper where we considered flavour changing couplings only in the
left-handed sector. We show that these new couplings have important
consequences leading to a large enhancement when the mixing of the scalar
partners of the left- and right-handed top quark is included. Furthermore CP
violation in the flavour changing top quark decay will occur when a SUSY phase
is taken into account.Comment: 14 pages, latex, 3 figure
Mid-infrared imaging- and spectro-polarimetric subarcsecond observations of NGC 1068
We present sub-arcsecond 7.513 m imaging- and spectro-polarimetric
observations of NGC 1068 using CanariCam on the 10.4-m Gran Telescopio
CANARIAS. At all wavelengths, we find:
(1) A 90 60 pc extended polarized feature in the northern ionization
cone, with a uniform 44 polarization angle. Its polarization
arises from dust and gas emission in the ionization cone, heated by the active
nucleus and jet, and further extinguished by aligned dust grains in the host
galaxy. The polarization spectrum of the jet-molecular cloud interaction at
24 pc from the core is highly polarized, and does not show a silicate
feature, suggesting that the dust grains are different from those in the
interstellar medium.
(2) A southern polarized feature at 9.6 pc from the core. Its
polarization arises from a dust emission component extinguished by a large
concentration of dust in the galaxy disc. We cannot distinguish between dust
emission from magnetically aligned dust grains directly heated by the jet close
to the core, and aligned dust grains in the dusty obscuring material
surrounding the central engine. Silicate-like grains reproduce the polarized
dust emission in this feature, suggesting different dust compositions in both
ionization cones.
(3) An upper limit of polarization degree of 0.3 per cent in the core. Based
on our polarization model, the expected polarization of the obscuring dusty
material is 0.1 per cent in the 813 m wavelength range. This
low polarization may be arising from the passage of radiation through aligned
dust grains in the shielded edges of the clumps.Comment: 17 pages, 10 figures, accepted for publication at MNRA
Decision Support System of Innovative High-Temperature Latent Heat Storage for Waste Heat Recovery in the Energy-Intensive Industry
Reductions in energy consumption, carbon footprint, equipment size, and cost are key objectives for the forthcoming energy-intensive industries roadmaps. In this sense, solutions such as waste heat recovery, which can be replicated into different sectors (e.g., ceramics, concrete, glass, steel, aluminium, pulp, and paper) are highly promoted. In this line, latent heat thermal energy storage (TES) contributes as an innovative technology solution to improve the overall system efficiency by recovering and storing industrial waste heat. To this end, phase-change material (PCM) selection is assisted through a decision-support system (DSS). A simplified tool based on the MATLAB(R) model, based on correlations among the most relevant system parameters, was developed to prove the feasibility of a cross-sectorial approach. The research work conducted a parametric analysis to assess the techno-economic performance of the PCM-TES solution under different working conditions and sectors. Additionally, a multicriteria assessment was performed comparing the tool outputs from metal alloys and inorganic hydrated PCM salts. Overall, the inorganic PCMs presented higher net economic and energy savings (up to 25, 000 euro/yr; 480 MWh/yr), while metal alloys involved promising results, shorter cycles, and competitive economic ratios; its commercial development is still limited
GU Boo: A New 0.6 Msun Detached Eclipsing Binary
We have found a new low-mass, double-lined, detached eclipsing binary, GU
Boo, among a sample of new variables from the ROTSE-I database. The binary has
an orbital period of 0.488728 +/- 0.000002 days, and estimated apparent
magnitudes Vrotse = 13.7 and I = 11.8. Our analysis of the light and radial
velocity curves of the system yields individual masses and radii of M1= 0.610
+/- 0.007 Msun, M2 = 0.599 +/- 0.006 Msun, R1= 0.623 +/- 0.016 Rsun, R2= 0.620
+/- 0.020 Rsun. The stars in GU Boo are therefore very similar to the
components of the eclipsing binary YY Gem. For this study we have adopted a
mean effective temperature for the binary of Teff = 3870 +/- 130 K. Based on
its space velocities we suggest that GU Boo is a main sequence binary, possibly
with an age of several Gyr. The metallicity of the binary is not well
constrained at this point but we speculate that it should not be very different
from solar. We have compared the physical parameters of GU Boo with current
low-mass stellar models, where we accounted for uncertainties in age and
metallicity by considering a wide range of values for those parameters. Our
comparisons reveal that all the models underestimate the radii of the
components of GU Boo by at least 10-15%. This result is in agreement with the
recent studies of YY Gem and CU Cnc.Comment: 41 pages, 10 figures, 11 tables; accepted by Ap
A major star formation region in the receding tip of the stellar Galactic bar. II. Supplementary information and evidence that the bar is not the same structure as the triaxial bulge previouly reported
This paper is the second part of Garzon et al. (1997: ApJ 491, L31) in which
we presented an outline of the analysis of 60 spectra from a follow-up program
to the Two Micron Galactic Survey (TMGS) project in the l=27 deg., b=0 deg.
area. In this second part, we present a more detailed explanation of the
analysis as well a library of the spectra for more complete information for
each of the 60 stars, and further discussions on the implications for the
structure of the Galaxy.
This region contains a prominent excess in the flux distribution and star
counts previously observed in several spectral ranges, notably in the TMGS.
More than 50% of the spectra of the stars detected with m_K<5.0 mag, within a
very high confidence level, correspond to stars of luminosity class I, and a
significant proportion of the remainder are very late giants which must also be
rapidly evolving. We make the case, using all the available evidence, that we
are observing a region at the nearer end of the Galactic bar, where the Scutum
spiral arm breaks away, and that this is powerful evidence for the presence of
the bar. Alternative explanations do not give nearly such a satisfactory
account of the observations.
The space localization of one and, a fortiori, of both ends of the bar allows
us to infer a position angle for the bar of around 75 deg. with respect to the
Sun-Galactic centre line. The angle is different from that given by other
authors for the bar and this, we think, is because they refer to the triaxial
bulge and not to the bar as detected here.Comment: 21 pages, 1 table, 9 figures, accepted in A
Black hole determinants and quasinormal modes
We derive an expression for functional determinants in thermal spacetimes as
a product over the corresponding quasinormal modes. As simple applications we
give efficient computations of scalar determinants in thermal AdS, BTZ black
hole and de Sitter spacetimes. We emphasize the conceptual utility of our
formula for discussing `1/N' corrections to strongly coupled field theories via
the holographic correspondence.Comment: 28 pages. v2: slightly improved exposition, references adde
Flavor changing t -> c l_1^- l_2^+ decay in the general two Higgs doublet model
We study the flavor changing t-> c l_1^- l_2^+ decay in the framework of the
general two Higgs doublet model, the so called model III. We predict the
branching ratio for l_1=\tau, l_2=\mu at the order of magnitude of BR \sim
10^{-8}.Comment: 12 Pages, 5 Figure
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