Families of Proper Holomorphic Embeddings and Carleman-Type Theorem with parameters

We solve the problem of simultaneously embedding properly holomorphically into C2 a whole family of n-connected domains Omega_r in P1 such that none of the components of P1 \ Omega_r reduces to a point, by constructing a continuous mapping such that is a proper holomorphic embedding for every r. To this aim, a parametric version of both the Andersén–Lempert procedure and Carleman’s Theorem is formulated and proved.publishedVersio

Families of Proper Holomorphic Embeddings and Carleman-type Theorems with parameters

We solve the problem of simultaneously embedding properly holomorphically into $\Bbb C^2$ a whole family of $n$-connected domains $\Omega_r\subset\Bbb P^1$ such that none of the components of $\Bbb P^1\setminus\Omega_r$ reduces to a point, by constructing a continuous mapping $\Xi\colon\bigcup_r\{r\}\times\Omega_r\to\Bbb C^2$ such that $\Xi(r,\cdot)\colon\Omega_r\hookrightarrow\Bbb C^2$ is a proper holomorphic embedding for every $r$. To this aim, a parametric version of both the Anders\'en-Lempert procedure and Carleman's Theorem is formulated and proved

On the late spectral types of cataclysmic variable secondaries

We investigate why the spectral type of most cataclysmic variable (CV) secondaries is significantly later than that of a ZAMS star with the same mean density. Using improved stellar input physics, tested against observations of low-mass stars at the bottom of the main sequence, we calculate the secular evolution of CVs with low-mass donors. We consider sequences with different mass transfer rates and with a different degree of nuclear evolution of the donor prior to mass transfer. Systems near the upper edge of the gap ($P \sim 3 - 6$ h) can be reproduced by models with a wide range of mass transfer rates from 1.5 \times 10^{-9} \msolyr to 10^{-8} \msolyr. Evolutionary sequences with a small transfer rate and donors that are substantially evolved off the ZAMS (central hydrogen content $0.05-0.5$) reproduce CVs with late spectral types above P \simgr 6 h. Systems with the most discrepant (late) spectral type should have the smallest donor mass at any given $P$. Consistency with the period gap suggests that the mass transfer rate increases with decreasing donor mass for evolved sequences above the period gap. In this case, a single-parameter family of sequences with varying \xc and increasing mass transfer rate reproduces the full range of observed spectral types. This would imply that CVs with such evolved secondaries dominate the CV population.Comment: 9 pages, Latex file, uses mn.sty, accepted for publication in MNRA

First XMM-Newton Observations of the Globular Cluster M22

We have examined preliminary data of the globular cluster, M22, from the EPIC MOS detectors on board XMM-Newton. We have detected 27 X-ray sources within the centre of the field of view, 24 of which are new detections. Three sources were found within the core of the cluster. From spectral analysis of the X-ray sources, it is possible that the object at the centre of the core is a quiescent X-ray transient and those lying further out are maybe cataclysmic variables.Comment: 6 pages, 3 figures, accepted to be published in Astronomy and Astrophysic

Renormalization as a functor on bialgebras

The Hopf algebra of renormalization in quantum field theory is described at a general level. The products of fields at a point are assumed to form a bialgebra B and renormalization endows T(T(B)^+), the double tensor algebra of B, with the structure of a noncommutative bialgebra. When the bialgebra B is commutative, renormalization turns S(S(B)^+), the double symmetric algebra of B, into a commutative bialgebra. The usual Hopf algebra of renormalization is recovered when the elements of B are not renormalised, i.e. when Feynman diagrams containing one single vertex are not renormalised. When B is the Hopf algebra of a commutative group, a homomorphism is established between the bialgebra S(S(B)^+) and the Faa di Bruno bialgebra of composition of series. The relation with the Connes-Moscovici Hopf algebra of diffeomorphisms is given. Finally, the bialgebra S(S(B)^+) is shown to give the same results as the standard renormalisation procedure for the scalar field.Comment: 24 pages, no figure. Several changes in the connection with standard renormalizatio

Pubarca precoce isolada e associada a hiperplasia adrenal congênita tardia : parâmetros clínicos, metabólicos e endocrinológicos

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Pubarca precoce isolada e associada a hiperplasia adrenal congênita tardia : parâmetros clínicos metabólicos e endocrinológicos

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Effects of eight-quark interactions on the hadronic vacuum and mass spectra of light mesons

The combined effective low energy QCD Lagrangians of Nambu -- Jona-Lasinio (NJL) and 't Hooft are supplemented with eight-quark interactions. This work is a follow-up of recent findings, namely (i) the six quark flavour determinant 't Hooft term destabilizes the NJL vacuum, (ii) the addition of a chiral invariant eight-fermion contact term renders the ground state of the theory globally stable; (iii) stability constrains the values of coupling constants of the model, meaning that even in the presence of eight-quark forces the system can be unstable in a certain parameter region. In the present work we study a phenomenological output of eight-quark interactions considering the mass spectra of pseudoscalar and scalar mesons. Mixing angles are obtained and their equivalence to the two angle approach is derived. We show that the masses of pseudoscalars are almost neutral to the eight-quark forces. The only marked effect of the second order in the SU(3) breaking is found in the $\eta -\eta'$ system. The scalars are more sensitive to the eight-quark interactions. A strong repulsion between the singlet-octet members is the reason for the obtained low mass of the $\sigma$ state within the model considered.Comment: LaTeX, 46 pages, two figure

The X-ray spectrum of the newly discovered accreting millisecond pulsar IGR J17511-3057

We report on an XMM-Newton observation of the accreting millisecond pulsar, IGR J17511-3057. Pulsations at 244.8339512(1) Hz are observed with an RMS pulsed fraction of 14.4(3)%. A precise solution for the P_orb=12487.51(2)s binary system is derived. The measured mass function indicates a main sequence companion with a mass between 0.15 and 0.44 Msun. The XMM-Newton spectrum of the source can be modelled by at least three components, multicoloured disc emission, thermal emission from the NS surface and thermal Comptonization emission. Spectral fit of the XMM-Newton data and of the RXTE data, taken in a simultaneous temporal window, constrain the Comptonization parameters: the electron temperature, kT_e=51(+6,-4) keV, is rather high, while the optical depth (tau=1.34(+0.03,-0.06)) is moderate. The energy dependence of the pulsed fraction supports the interpretation of the cooler thermal component as coming from the accretion disc, and indicates that the Comptonizing plasma surrounds the hot spots on the NS surface, which provide the seed photons. Signatures of reflection, such as a broadened iron K-alpha emission line and a Compton hump at 30 keV ca., are also detected. We derive from the smearing of the reflection component an inner disc radius of ~> 40 km for a 1.4 Msun neutron star, and an inclination between 38{\deg} and 68{\deg}. XMM-Newton also observed two type-I X-ray bursts, probably ignited in a nearly pure helium environment. No photospheric radius expansion is observed, thus leading to an upper limit on the distance to the source of 10 kpc. A lower limit of 6.5 kpc can be also set if it is assumed that emission during the decaying part of the burst involves the whole neutron star surface. Pulsations observed during the burst decay are compatible with being phase locked, and have a similar amplitude, than pre-burst pulsations.Comment: 16 pages, 10 figures, 4 tables, accepted for publication in MNRA

The variability plane of accreting compact objects

Recently, it has been shown that soft-state black hole X-ray binaries and active galactic nuclei populate a plane in the space defined by the black hole mass, accretion rate and characteristic frequency. We show that this plane can be extended to hard-state objects if one allows a constant offset for the frequencies in the soft and the hard state. During a state transition the frequencies rapidly move from one scaling to the other depending on an additional parameter, possibly the disk-fraction. The relationship between frequency, mass and accretion rate can be further extended by including weakly accreting neutron stars. We explore if the lower kHz QPOs of neutron stars and the dwarf nova oscillations of white dwarfs can be included as well and discuss the physical implications of the found correlation.Comment: Accepted for publication in MNRA