893 resultados para Field of force
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We propose a framework to describe the cooperative orientational motions of water molecules in liquid water and around solute molecules in water solutions. From molecular dynamics (MD) simulation a new quantity “site-dipole field” is defined as the averaged orientation of water molecules that pass through each spatial position. In the site-dipole field of bulk water we found large vortex-like structures of more than 10 Å in size. Such coherent patterns persist more than 300 ps although the orientational memory of individual molecules is quickly lost. A 1-ns MD simulation of systems consisting of two amino acids shows that the fluctuations of site-dipole field of solvent are pinned around the amino acids, resulting in a stable dipole-bridge between side-chains of amino acids. The dipole-bridge is significantly formed even for the side-chain separation of 14 Å, which corresponds to five layers of water. The way that dipole-bridge forms sensitively depends on the side-chain orientations and thereby explains the specificity in the solvent-mediated interactions between biomolecules.
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We report on the long-term X-ray monitoring of the outburst decay of the low magnetic field magnetar SGR 0418+5729 using all the available X-ray data obtained with RXTE, Swift, Chandra, and XMM-Newton observations from the discovery of the source in 2009 June up to 2012 August. The timing analysis allowed us to obtain the first measurement of the period derivative of SGR 0418+5729: ˙ P = 4(1) × 10−15 s s−1, significant at a ∼3.5σ confidence level. This leads to a surface dipolar magnetic field of Bdip 6 × 1012 G. This measurement confirms SGR 0418+5729 as the lowest magnetic field magnetar. Following the flux and spectral evolution from the beginning of the outburst up to ∼1200 days, we observe a gradual cooling of the tiny hot spot responsible for the X-ray emission, from a temperature of ∼0.9 to 0.3 keV. Simultaneously, the X-ray flux decreased by about three orders of magnitude: from about 1.4 × 10−11 to 1.2 × 10−14 erg s−1 cm−2. Deep radio, millimeter, optical, and gamma-ray observations did not detect the source counterpart, implying stringent limits on its multi-band emission, as well as constraints on the presence of a fossil disk. By modeling the magneto-thermal secular evolution of SGR 0418+5729, we infer a realistic age of ∼550 kyr, and a dipolar magnetic field at birth of ∼1014 G. The outburst characteristics suggest the presence of a thin twisted bundle with a small heated spot at its base. The bundle untwisted in the first few months following the outburst, while the hot spot decreases in temperature and size. We estimate the outburst rate of low magnetic field magnetars to be about one per year per galaxy, and we briefly discuss the consequences of such a result in several other astrophysical contexts.
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We report on the long-term X-ray monitoring with Swift, RXTE, Suzaku, Chandra, and XMM-Newton of the outburst of the newly discovered magnetar Swift J1822.3–1606 (SGR 1822–1606), from the first observations soon after the detection of the short X-ray bursts which led to its discovery, through the first stages of its outburst decay (covering the time span from 2011 July until the end of 2012 April). We also report on archival ROSAT observations which detected the source during its likely quiescent state, and on upper limits on Swift J1822.3–1606's radio-pulsed and optical emission during outburst, with the Green Bank Telescope and the Gran Telescopio Canarias, respectively. Our X-ray timing analysis finds the source rotating with a period of P = 8.43772016(2) s and a period derivative P = 8.3(2)×10−14 s s−1, which implies an inferred dipolar surface magnetic field of B sime 2.7 × 1013 G at the equator. This measurement makes Swift J1822.3–1606 the second lowest magnetic field magnetar (after SGR 0418+5729). Following the flux and spectral evolution from the beginning of the outburst, we find that the flux decreased by about an order of magnitude, with a subtle softening of the spectrum, both typical of the outburst decay of magnetars. By modeling the secular thermal evolution of Swift J1822.3–1606, we find that the observed timing properties of the source, as well as its quiescent X-ray luminosity, can be reproduced if it was born with a poloidal and crustal toroidal fields of Bp ~ 1.5 × 1014 G and B tor ~ 7 × 1014 G, respectively, and if its current age is ~550 kyr.
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This is a guide to develop a theoretical framework for any field of knowledge. It is a rational and organized to put everything that is known or has been written about an issue or a problem way.
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We perform a detailed modelling of the post-outburst surface emission of the low magnetic field magnetar SGR 0418+5729. The dipolar magnetic field of this source, B=6×1012G estimated from its spin-down rate, is in the observed range of magnetic fields for normal pulsars. The source is further characterized by a high pulse fraction and a single-peak profile. Using synthetic temperature distribution profiles, and fully accounting for the general-relativistic effects of light deflection and gravitational redshift, we generate synthetic X-ray spectra and pulse profiles that we fit to the observations. We find that asymmetric and symmetric surface temperature distributions can reproduce equally well the observed pulse profiles and spectra of SGR 0418. None the less, the modelling allows us to place constraints on the system geometry (i.e. the angles ψ and ξ that the rotation axis makes with the line of sight and the dipolar axis, respectively), as well as on the spot size and temperature contrast on the neutron star surface. After performing an analysis iterating between the pulse profile and spectra, as done in similar previous works, we further employed, for the first time in this context, a Markov-Chain Monte Carlo approach to extract constraints on the model parameters from the pulse profiles and spectra, simultaneously. We find that, to reproduce the observed spectrum and flux modulation: (a) the angles must be restricted to 65° ≲ ψ + ξ ≲ 125° or 235° ≲ ψ + ξ ≲ 295°; (b) the temperature contrast between the poles and the equator must be at least a factor of ∼6, and (c) the size of the hottest region ranges between 0.2 and 0.7 km (including uncertainties on the source distance). Lastly, we interpret our findings within the context of internal and external heating models.
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[Introduction.] It is generally believed that while the principle of the autonomy of the EU legal order, in the sense of constitutional and institutional autonomy that is to say what concerns the autonomous decision-making of the EU, has been clearly strengthened by the most recent jurisprudence of the Court of Justice (eg. Moxplant3, Intertanko or the Kadi/Al Baraakat judgements or the Opinion 1/2009 of the CJEU etc.) as well as, in my opinion, in many aspects by the Treaty of Lisbon, it is still valid to add that the principle of a favourable approach, stemming from the Court jurisprudence, for the enhanced openness of the EU legal order to international law has remained equally important for the EU4. On the other hand, it should be also seen that in a globalized world, and following the increased role of the EU as an international actor, its indispensable and crucial role concerning the creation of world (legal) order in many policy fields ( for example let's think about the G20 issues, the global economic and financial crisis, the role of the EU in promoting and protecting human rights worldwide, the implementation of the multilateral or regional conventional law, developed in the framework the UN (e.g. in the field of agriculture or environment etc) or what concerns the Kyoto process on climate change or the conservation of marine biological resources at international level etc), it seems reasonable and justified to submit that the influence, for example, of the law-making activities of the main stakeholder international organizations in the mentioned policy-areas on the EU (especially on the development of its constantly evolving legal order) or vice-versa the influence of the EU law-making practice on these international organizations is significant, in many aspects mutually interdependent and more and more remarkable. This tendency of the 21st century doesn't mean, however, in my view, that the notion of the autonomy of the EU legal order would have been weakened by this increasing interaction between international law and EU law over the passed years. This contribution is going to demonstrate and prove these departuring points by giving some concrete examples from the most recent practice of the Council (all occuring either in the second half of 2009 or after the entry into force of the Lisbon Treaty), and which relate to two very important policy areas in the EU, namely the protection of human rights and the Common Fishery Policy.
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Introduction. Unintended as it was, the European Court of Justice (ECJ, the Court, the Court of the EU) has played an extremely important role in the construction of the Area of Freedom Security and Justice (AFSJ). The AFSJ was set up by the Treaty of Amsterdam in 1997 and only entered into force in May 1999. The fact that this is a new field of EU competence, poses afresh all the fundamental questions – both political and legal – triggered by European integration, namely in terms of: a) distribution of powers between the Union and its Member States, b) attribution of competences between the various EU Institutions, c) direct effect and supremacy of EU rules, d) scope of competence of the ECJ, and e) extent of the protection given to fundamental rights. The above questions have prompted judicial solutions which take into account both the extremely sensible fields of law upon which the AFSJ is anchored, and the EU’s highly inconvenient three-pillar institutional framework.1 The ECJ is the body whose institutional role is to benefit most from this upcoming ‘depilarisation’, possibly more than that of the European Parliament. This structure is on the verge of being abandoned, provided the Treaty of Lisbon enters into force.2 However spectacular this formal boost of the Court’s competence, the changes in real terms are not going to be that dramatic. This apparent contradiction is explained, to a large extent, by the fact that the Court has in many ways ‘provoked’, or even ‘anticipated’, the depilarisation of its own jurisdictional role, already under the existing three-pillar structure. Simply put, under the new – post Treaty of Lisbon – regime, the Court will have full jurisdiction over all AFSJ matters, as those are going to be fully integrated in what is now the first pillar. Some limitations will continue to apply, however, while a special AFSJ procedure will be institutionalised. Indeed, if we look into the new Treaty we may identify general modifications to the Court’s structure and jurisdiction affecting the AFSJ (section 2), modifications in the field of the AFSJ stemming from the abolition of the pillar structure (section 3) and, finally, some rules specifically applicable to the AFSJ (section 4).
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Years of uncoordinated cuts in defence spending have eroded the EU’s role as a security actor in what is now a multipolar world. This CEPS Task Force report aims to provide member states and the EU institutions with the narrative to strengthen defence cooperation in the EU, in the face of numerous emergencies in the EU’s strategic neighbourhood and ever-present security threats. The report is a record of the deliberations over several months between high-level experts in the field of European security and defence, who conclude that the Treaty of Lisbon demands and permits a great deal more in terms of our common security and defence activities. And that member states could achieve much more value for money than the €190 billion that they spend to keep up 28 national armies, comprising roughly 1.5 million service personnel. This report suggests policy actions to further the EU’s strategic, institutional, capabilities, and resources cooperation in the field of defence. Ultimately, in the view of the Task Force experts, further integration should amount to a European Defence Union.
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During DSDP Leg 65, we achieved significant basement penetration at three sites (482, 483, and 485) in the mouth of the Gulf of California (Lewis and Robinson, 1983, doi:10.2973/dsdp.proc.65.1983). Since these holes were all drilled into extremely young crust near the crest of the East Pacific Rise, the rocks we recovered present an unusual opportunity to study the magnetic properties of submarine basalts before alteration has become pervasive. To take advantage of this opportunity and to complement the paleomagnetic studies conducted on these basalts by Day (1983, doi:10.2973/dsdp.proc.65.138.1983), we have studied, in the same samples, the following properties: saturation magnetization (Js); intensity and stability of isothermal remanent magnetization (IRM); hysteresis parameters, such as the coercive force (Hc), the remanent coercive force (HRC), and the ratio of saturation remanence (JRS) to saturation magnetization; susceptibility (x); and Curie temperature (Tc). In this chapter we will discuss the results of these studies in conjunction with the opaque mineralogy of the samples.
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Thesis (Ph.D.)--University of Washington, 2016-06