1,751 research outputs found
Electroweak phase transition in technicolor
Several phenomenologically viable walking technicolor models have been
proposed recently. I demonstrate that these models can have first order
electroweak phase transitions, which are sufficiently strong for electroweak
baryogenesis. Strong dynamics can also lead to several separate transitions at
the electroweak scale, with the possibility of a temporary restoration and an
extra breaking of the electroweak symmetry. First order phase transitions will
produce gravitational waves, which may be detectable at future experiments.Comment: 6 pages, 4 figures. Talk at PASCOS 2010 conference, Valencia, 19-23
July 201
Information completeness in Nelson algebras of rough sets induced by quasiorders
In this paper, we give an algebraic completeness theorem for constructive
logic with strong negation in terms of finite rough set-based Nelson algebras
determined by quasiorders. We show how for a quasiorder , its rough
set-based Nelson algebra can be obtained by applying the well-known
construction by Sendlewski. We prove that if the set of all -closed
elements, which may be viewed as the set of completely defined objects, is
cofinal, then the rough set-based Nelson algebra determined by a quasiorder
forms an effective lattice, that is, an algebraic model of the logic ,
which is characterised by a modal operator grasping the notion of "to be
classically valid". We present a necessary and sufficient condition under which
a Nelson algebra is isomorphic to a rough set-based effective lattice
determined by a quasiorder.Comment: 15 page
Mapping EK Draconis with PEPSI - Possible evidence for starspot penumbrae
We present the first temperature surface map of EK Dra from
very-high-resolution spectra obtained with the Potsdam Echelle Polarimetric and
Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope. Changes in
spectral line profiles are inverted to a stellar surface temperature map using
our Map code. The long-term photometric record is employed to compare our
map with previously published maps. Four cool spots were reconstructed, but no
polar spot was seen. The temperature difference to the photosphere of the spots
is between 990 and 280K. Two spots are reconstructed with a typical solar
morphology with an umbra and a penumbra. For the one isolated and relatively
round spot (A), we determine an umbral temperature of 990K and a penumbral
temperature of 180K below photospheric temperature. The umbra to photosphere
intensity ratio of EK Dra is approximately only half of that of a comparison
sunspot. A test inversion from degraded line profiles showed that the higher
spectral resolution of PEPSI reconstructs the surface with a temperature
difference that is on average 10% higher than before and with smaller surface
areas by 10-20%. PEPSI is therefore better suited to detecting and
characterising temperature inhomogeneities. With ten more years of photometry,
we also refine the spot cycle period of EK Dra to 8.90.2 years with a
continuing long-term fading trend. The temperature morphology of spot A so far
appears to show the best evidence for the existence of a solar-like penumbra
for a starspot. We emphasise that it is more the non-capture of the true umbral
contrast rather than the detection of the weak penumbra that is the limiting
factor. The relatively small line broadening of EK Dra, together with the only
moderately high spectral resolutions previously available, appear to be the
main contributors to the lower-than-expected spot contrasts when comparing to
the Sun.Comment: Accepted for A&
Renal Tumor Invasion Depth and Diameter are the Two Most Accurate Anatomical Features Regarding the Choice of Radical Versus Partial Nephrectomy
Background and Aims: To evaluate simple tumor characteristics (renal tumor diameter and parenchymal invasion depth) compared with more complex classifications, that is, Renal Tumor Invasion Index (RTII) and Preoperative Aspects and Dimensions Used for an Anatomical classification, in predicting the type of nephrectomy (radical vs partial) performed. Material and Methods: A total of 915 patients who had undergone either partial nephrectomy (n=388, 42%) or radical nephrectomy (n=527, 58%) were identified from the Helsinki University Hospital kidney tumor database between 1 January 2006 and 31 December 2014. Tumor maximum diameter and depth of invasion into the parenchyma were estimated from computed tomography or magnetic resonance imaging images and compared with Preoperative Aspects and Dimensions Used for an Anatomical and Renal Tumor Invasion Index. Logistic regression and receiver operating curves were used to compare the parameters at predicting the type of nephrectomy. Results and conclusion: All the anatomical variables of receiver operating curve/area under the curve analyses were significant predictors for the type of nephrectomy. Parenchymal invasion (area under the curve 0.91; 95% confidence interval, 0.89-0.93), RTII (area under the curve 0.91; 95% confidence interval, 0.89-0.93), and diameter (area under the curve 0.91; 95% confidence interval, 0.89-0.93) performed significantly better than Preoperative Aspects and Dimensions Used for an Anatomical classification (area under the curve 0.88; 95% confidence interval, 0.85-0.89). In multivariable analysis, invasion depth was the best predictor of nephrectomy type (percentage correct, 85.6%). Addition of one anatomic parameter into the model of non-anatomical cofactors improved the accuracy of the model significantly, but the addition of more parameters did not. Parenchymal invasion depth and tumor diameter are the most accurate anatomical features for predicting the nephrectomy type. All potential anatomical classification systems should be tested against these two simple characteristics.Peer reviewe
HD149277: A rare short-period SB2 system with a subsynchronously rotating magnetic He-rich primary
HD149277 is a rare SB2 system with a slowly rotating magnetic He-rich primary with Prot = 25.4 d. The CFHT/ESPaDOnS archive spectra revealed Porb = 11.5192 ± 0.0005 d indicating strong subsynchronous rotation of the primary component. Such a strong subsynchronous rotation was not detected in any other SB2 system with a magnetic chemically peculiar component. Our inspection of the spectra revealed the presence of resolved Zeeman split spectral lines allowing us to determine the variability of the mean magnetic field modulus over the rotation period. The maximum of the magnetic field modulus coincides roughly with the positive extremum of the longitudinal field, whereas the minimum of the modulus with the negative extremum of the longitudinal field. No evidence for a longitudinal magnetic field was seen in the circularly polarized spectra of the secondary component. Using archival data from the ASAS3 survey, we find in the frequency spectrum only one significant peak, corresponding to the period Pphot = 25.390 ± 0.014 d. This value is in good agreements with the previous determination of the rotation period, Prot =25.380±0.007 d, which was based on longitudinal magnetic field measurements.Fil: Gonzalez, Jorge Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Hubrig, S.. Leibniz Institute For Astrophysics Potsdam; AlemaniaFil: Järvinen, S. P.. Leibniz Institute For Astrophysics Potsdam; AlemaniaFil: Schöller, M.. European Southern Observatory; Alemani
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