304 research outputs found

    Classical nonintegrability of a quantum chaotic SU(3) Hamiltonian system

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    We prove nonintegrability of a model Hamiltonian system defined on the Lie algebra su3\mathfrak{su}_3 suitable for investigation of connections between classical and quantum characteristics of chaos.Comment: 17 page

    Analysis of new high-precision transit light curves of WASP-10 b: starspot occultations, small planetary radius, and high metallicity

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    The WASP-10 planetary system is intriguing because different values of radius have been reported for its transiting exoplanet. The host star exhibits activity in terms of photometric variability, which is caused by the rotational modulation of the spots. Moreover, a periodic modulation has been discovered in transit timing of WASP-10 b, which could be a sign of an additional body perturbing the orbital motion of the transiting planet. We attempt to refine the physical parameters of the system, in particular the planetary radius, which is crucial for studying the internal structure of the transiting planet. We also determine new mid-transit times to confirm or refute observed anomalies in transit timing. We acquired high-precision light curves for four transits of WASP-10 b in 2010. Assuming various limb-darkening laws, we generated best-fit models and redetermined parameters of the system. The prayer-bead method and Monte Carlo simulations were used to derive error estimates. Three transit light curves exhibit signatures of the occultations of dark spots by the planet during its passage across the stellar disk. The influence of stellar activity on transit depth is taken into account while determining system parameters. The radius of WASP-10 b is found to be no greater than 1.03 Jupiter radii, a value significantly smaller than most previous studies indicate. We calculate interior structure models of the planet, assuming a two-layer structure with one homogeneous envelope atop a rock core. The high value of the WASP-10 b's mean density allows one to consider the planet's internal structure including 270 to 450 Earth masses of heavy elements. Our new mid-transit times confirm that transit timing cannot be explained by a constant period if all literature data points are considered. They are consistent with the ephemeris assuming a periodic variation of transit timing...Comment: Accepted for publication in A&

    Phantom cosmology as a scattering process

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    We study the general chaotic features of dynamics of the phantom field modelled in terms of a single scalar field conformally coupled to gravity. We demonstrate that the dynamics of the FRW model with dark energy in the form of phantom field can be regarded as a scattering process of two types: multiple chaotic and classical non-chaotic. It depends whether the spontaneously symmetry breaking takes place. In the first class of models with the spontaneously symmetry breaking the dynamics is similar to the Yang-Mills theory. We find the evidence of a fractal structure in the phase space of initial conditions. We observe similarities to the phenomenon of a multiple scattering process around the origin. In turn the class of models without the spontaneously symmetry breaking can be described as the classical non-chaotic scattering process and the methods of symbolic dynamic are also used in this case. We show that the phantom cosmology can be treated as a simple model with scattering of trajectories which character depends crucially on a sign of a square of mass. We demonstrate that there is a possibility of chaotic behavior in the flat Universe with a conformally coupled phantom field in the system considered on non-zero energy level. We obtain that the acceleration is a generic feature in the considered model without the spontaneously symmetry breaking. We observe that the effective EOS coefficient oscillates and then approach to w=1w=-1.Comment: RevTeX4, 19 pages, 17 figures; v2 - added a comment on the Yang-Mills cosmological models and bibliography; v3 - added a section on acceleration, 2 figures, some references

    Towards the Rosetta Stone of planet formation

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    Transiting exoplanets (TEPs) observed just about 10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs), the radius of the planet could indicate whether planets form by gravitational collapse (being larger when young) or accretion growth (being smaller when young). We present a survey, the main goal of which is to find and then characterise TEPs in very young open clusters.Comment: Poster contribution to Detection and Dynamics of Transiting Exoplanets (Haute Provence Observatory Colloquium, 23-27 August 2010

    False-positive radioiodine whole-body scan due to a renal cyst

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    Patients affected by differentiated thyroid cancer are treated surgically and by ablative radioiodine therapy. A post-therapy whole-body scan allows detection of thyroid remnants or local and distant metastases, although false-positive findings may be observed. We report a case of a 75-year-old woman with follicular thyroid cancer, who underwent ablative radioiodine treatment. On post-therapy wholebody scan, abnormal uptake in the left upper abdomen was found, although stimulated thyroglobulin level was not suggestive for distant metastases of differentiated thyroid carcinoma. Additional SPECT/CT acquisition revealed focal 131I uptake located at the posterolateral wall of the left kidney corresponding to a round lesion 47 mm in maximal diameter. In order to verify this finding abdominal ultrasound and abdominal contrast-enhanced CT were performed, confirming multiple renal cysts in the left kidney; the largest one was the site of abnormal radioiodine accumulation. Despite the high incidence of renal cysts, especially in the elderly, radioiodine uptake in renal cystsis extremely rare. Different hypotheses on the mechanism of radioiodine uptake in the cyst were proposed, among them active secretion by sodium-iodide symporter or other transporting proteins. We conclude that abnormal radioiodine uptake in renal cysts can be an exceptional finding mimicking a metastasis

    A Possible Detection of Occultation by a Proto-planetary Clump in GM Cephei

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    GM Cep in the young (~4 Myr) open cluster Trumpler 37 has been known to be an abrupt variable and to have a circumstellar disk with very active accretion. Our monitoring observations in 2009-2011 revealed the star to show sporadic flare events, each with brightening of < 0.5 mag lasting for days. These brightening events, associated with a color change toward the blue, should originate from an increased accretion activity. Moreover, the star also underwent a brightness drop of ~1 mag lasting for about a month, during which the star became bluer when fainter. Such brightness drops seem to have a recurrence time scale of a year, as evidenced in our data and the photometric behavior of GM Cep over a century. Between consecutive drops, the star brightened gradually by about 1 mag and became blue at peak luminosity. We propose that the drop is caused by obscuration of the central star by an orbiting dust concentration. The UX Orionis type of activity in GM Cep therefore exemplifies the disk inhomogeneity process in transition between grain coagulation and planetesimal formation in a young circumstellar disk.Comment: In submission to the Astrophysical Journal, 4 figure

    Does the type of a centre in which the resection of extensive tumours of the limbs and truck is performed, affect the patients’ survival?

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    Nowoczesna chirurgia rekonstrukcyjna opiera się na odpowiednim wykorzystaniu dostępnych metod rekonstrukcyjnych, w tym mikronaczyniowych. Zaplanowanie odpowiedniej operacji rekonstrukcyjnej daje możliwość wykonania maksymalnie szerokiej resekcji, co dodatkowo zwiększa radykalność zabiegu. Ostatnimi czasy zaznacza się tendencja do wykonywania rozległych resekcji nowotworów w ośrodkach nie dysponujących bogatym doświadczeniem w tego rodzaju procedurach. Istnieje obawa, że, z uwagi na brak możliwości wykonania jednoczasowej rekonstrukcji, zakres resekcji może być niewystarczający do uzyskania pełnej radykalności zabiegu. W oparciu o wyniki badań 71 chorych leczonych w Klinice Chirurgii Onkologicznej i Rekonstrukcyjnej w latach 2006 – 2017 z powodu rozległych zmian nowotworowych tułowia i kończyn wykazano, że chorzy leczeni pierwotnie (zabieg resekcyjny) poza Instytutem charakteryzowali się znacząco krótszym czasem przeżycia do wznowy. Powyższe wyniki stanowią głos potwierdzający zasadność przeprowadzania rozległych zabiegów resekcyjno – rekonstrukcyjnych w przypadku zaawansowanych zmian nowotworowych, w ośrodkach o bogatym doświadczeniu w tym zakresie
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