4,799 research outputs found

    On the Axisymmetric Force-Free Pulsar Magnetosphere

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    We investigate the axisymmetric magnetosphere of an aligned rotating magnetic dipole surrounded by an ideal force-free plasma. We concentrate on the magnetic field structure around the point of intersection of the separatrix between the open and closed field-line regions and the equatorial plane. We first study the case where this intersection point is located at the Light Cylinder. We find that in this case the separatrix equilibrium condition implies that all the poloidal current must return to the pulsar in the open-field region, i.e., that there should be no finite current carried by the separatrix/equator current sheet. We then perform an asymptotic analysis of the pulsar equation near the intersection point and find a unique self-similar solution; however, a Light Surface inevitably emerges right outside the Light Cylinder. We then perform a similar analysis for the situation where the intersection point lies somewhere inside the Light Cylinder, in which case a finite current flowing along the separatrix and the equator is allowed. We find a very simple behavior in this case, characterized by a 90-degree angle between the separatrix and the equator and by finite vertical field in the closed-field region. Finally, we discuss the implications of our results for global numerical studies of pulsar magnetospheres.Comment: 31 pages, including 5 figure

    On Airy Solutions of the Second Painleve Equation

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    In this paper, we discuss Airy solutions of the second Painleve equation and two related equations, the Painleve XXXIV equation and the Jimbo-Miwa-Okamoto sigma form of second Painleve equation, are discussed. It is shown that solutions which depend only on the Airy function Ai(z) have a completely difference structure to those which involve a linear combination of the Airy functions Ai(z) and Bi(z). For all three equations, the special solutions that depend only on inline image are tronquƩe solutions, i.e., they have no poles in a sector of the complex plane. Further, for both inline image and SII, it is shown that among these tronquƩe solutions there is a family of solutions that have no poles on the real axis

    Nucleon-deuteron scattering with the JISP16 potential

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    The nucleon-nucleon J-matrix Inverse Scattering Potential JISP16 is applied to elastic nucleon-deuteron (Nd) scattering and the deuteron breakup process at the lab. nucleon energies up to 135 MeV. The formalism of the Faddeev equations is used to obtain 3N scattering states. We compare predictions based on the JISP16 force with data and with results based on various NN interactions: the CD Bonn, the AV18, the chiral force with the semi-local regularization at the 5th order of the chiral expansion and with low-momentum interactions obtained from the CD Bonn force as well as with the predictions from the combination of the AV18 NN interaction and the Urbana IX 3N force. JISP16 provides a satisfactory description of some observables at low energies but strong deviations from data as well as from standard and chiral potential predictions with increasing energy. However, there are also polarization observables at low energies for which the JISP16 predictions differ from those based on the other forces by a factor of two. The reason for such a behavior can be traced back to the P-wave components of the JISP16 force. At higher energies the deviations can be enhanced by an interference with higher partial waves and by the properties of the JISP16 deuteron wave function. In addition, we compare the energy and angular dependence of predictions based on the JISP16 force with the results of the low-momentum forces obtained with different values of the momentum cutoff parameter. We found that such low-momentum forces can be employed to interpret the Nd elastic scattering data only below some specific energy which depends on the cutoff parameter. Since JISP16 is defined in a finite oscillator basis, it has properties similar to low momentum interactions and its application to the description of Nd scattering data is limited to a low momentum transfer region.Comment: 26 pages, 12 eps figures; Version accepted to Phys. Rev. C: text is shortened, few figures regarding the nucleon-deuteron elastic scattering observables are removed but a short discussion of the nucleon induced deuteron breakup cross section is added. Conclusions remain unchange

    New Bifunctional Antioxidants : In tramolecular Synergistic Effects between Benzofuranol and Thiopropionate Group, Part II

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    The antioxidant activities of benzofuranols and chromanols with methyl, methyl thiomethyl and thiopropionate groups were evaluated for the oxidation of tetralin at 61 and 140ā„ƒ. The antioxidants tested showed almost the same behaviour for the oxidation of tetralin initiated by an azo initiator at 61ā„ƒ. However, benzofuranol and chromanol with a thiopropionate group at the meta position of the OH group were shown to improve antioxidant activity at high temperature to a greater extent than the methyl and methyl thiomethyl groups

    Communication with Families in the Last Days of a Patientā€™s Life and Optimal Delivery of a Death Pronouncement

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    Communicating with family members is critically important when a severely ill patient is experiencing their last few days of life. However, healthcare professionals (HCPs) have limited opportunities to learn effective and respectful ways to perform this communication. In recent decades, significant effort has been put forth to identify the phenomena that indicate the last hours and days of life and the optimal methods to deliver a death pronouncement, which will potentially help HCPs communicate compassionately with family members throughout the dying process. In this chapter, we will review the literature regarding the phenomena that indicate the last hours and days of life and the death pronouncement. Furthermore, we will discuss clinical implications derived from those articles and future research perspectives

    Alkali-metal-induced Fermi level and two dimensional electrons at cleaved InAs(110) surfaces

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    Low-temperature Hall measurements have been performed on two-dimensional electron gases (2DEGs) induced by deposition of Cs or Na on in situ cleaved surfaces of p-type InAs. The surface donor level, at which the Fermi energy of the 2DEG is pinned, is calculated from the observed saturation surface electron density using a surface potential determined self-consistently. The results are compared to those of previous photoelectron spectroscopy measurements.Comment: 3 pages, 4 figure
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