13 research outputs found

    Gravitational Wave Emission from Galactic Radio Pulsars

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    We consider in this work continuous gravitational wave (GW) emission from non-axisymmetric radio pulsars. We treat in some detail the observational issues related to the known radio pulsar sample with the aim of unveiling the actual number of sources contributing to GW, which are likely to be the main contributors of GWs. It is shown that the operation of spheroidal GW detectors and full-size interferometers could detect this component of the radiation or impose useful limits on the effective oblateness of young radio pulsars.Comment: 7 pages, RevTex , no figures , to appear in Phys. Rev.

    Magnetic Field Generation in Stars

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    Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe

    EFEITO ANALGÉSICO DO BUTORFANOL NA DOR SOMÁTICA EM GATOS ANESTESIADOS COM PROPOFOL ANALGESIC EFFECT OF BUTORPHANOL ON SOMATIC PAIN IN CATS ANESTHETIZED WITH PROPOFOL

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    O propofol é um agente anestésico intravenoso usado para indução e manutenção da anestesia, mas produz analgesia limitada, havendo a necessidade do uso concomitante de analgésicos. Avaliou-se o efeito analgésico do butorfanol na dor somática em gatos anestesiados com doses fracionadas de propofol. Foram utilizados 16 animais, distribuídos aleatoriamente em dois grupos. Os animais do grupo controle foram pré-tratados com 0,2mg/kg de acepromazina por via IM e, após 15 minutos, receberam 6mg/kg de propofol por via IV. Os animais do grupo tratamento foram pré-medicados com uma combinação de acepromazina (0,2mg/kg) e butorfanol (0,8mg/kg), administrados na mesma seringa por via IM, e, após 15 minutos, receberam 6mg/kg de propofol por via IV. Em ambos os grupos, a manutenção da anestesia foi feita com administrações de propofol, na dose de 3mg/kg, por via IV, sempre que necessário, durante 60 minutos. A necessidade de readministração de propofol foi verificada pela resposta apresentada ao pinçamento cutâneo, através de uma pinça de Kocher. Avaliaram-se também as freqüências cardíaca e respiratória, pressão arterial média, saturação de oxiemoglobina e temperatura retal. A administração de butorfanol causou apenas redução nas freqüências cardíaca e respiratória e na saturação de oxiemoglobina, em comparação com o grupo controle,sem exercer influência significativa sobre o período hábil, a dose total administrada e o período de recuperação do propofol. Concluiu-se que a adição de butorfanol não produziu analgesia somática em gatos anestesiados com doses fracionadas de propofol.<br>Propofol is an intravenous anesthetic agent used for induction and maintenance of anesthesia but produces limited analgesia, and concomitant use of analgesics is necessary. The analgesic effect of butorphanol in somatic pain in cats anesthetized with intermittent doses of propofol was evaluated. Sixteen animals were randomly assigned to 2 groups. Control group animals were premedicated with IM acepromazine (0,2mg/kg) and after 15 minutes IV propofol (6mg/kg) was administered. Treatment group animals were premedicated with IM acepromazine (0,2mg/kg) and butorphanol (0,8mg/kg), mixed in the same syringe and after 15 minutes IV propofol (6mg/kg) was administered. In both groups anesthesia was maintained with repeated injections of propofol (3mg/kg) as needed, during 60 minutes. The need to complement propofol doses was determined by reactions to a skin pinch with a Kocher hemostatic forceps.Heart rate, respiratory rate, mean blood pressure, rectal body temperature and oxyhemoglobin saturation were also recorded. Administration of butorphanol caused minimal changes in cardiopulmonary variables compared to control group and did not affect duration of anesthesia and total dose of propofol or recovery period. We concluded that addition of butorphanol did not produce somatic analgesia during anesthesia maintained with repeated injections of propofol in cats
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