Statistical Studies of Giant Pulse Emission from the Crab Pulsar

We have observed the Crab pulsar with the Deep Space Network (DSN) Goldstone 70 m antenna at 1664 MHz during three observing epochs for a total of 4 hours. Our data analysis has detected more than 2500 giant pulses, with flux densities ranging from 0.1 kJy to 150 kJy and pulse widths from 125 ns (limited by our bandwidth) to as long as 100 microseconds, with median power amplitudes and widths of 1 kJy and 2 microseconds respectively. The most energetic pulses in our sample have energy fluxes of approximately 100 kJy-microsecond. We have used this large sample to investigate a number of giant-pulse emission properties in the Crab pulsar, including correlations among pulse flux density, width, energy flux, phase and time of arrival. We present a consistent accounting of the probability distributions and threshold cuts in order to reduce pulse-width biases. The excellent sensitivity obtained has allowed us to probe further into the population of giant pulses. We find that a significant portion, no less than 50%, of the overall pulsed energy flux at our observing frequency is emitted in the form of giant pulses.Comment: 19 pages, 17 figures; to be published in Astrophysical Journa

Short photoperiod-induced decrease of histamine H3 receptors facilitates activation of hypothalamic neurons in the Siberian Hamster

Nonhibernating seasonal mammals have adapted to temporal changes in food availability through behavioral and physiological mechanisms to store food and energy during times of predictable plenty and conserve energy during predicted shortage. Little is known, however, of the hypothalamic neuronal events that lead to a change in behavior or physiology. Here we show for the first time that a shift from long summer-like to short inter-like photoperiod, which induces physiological adaptation to winter in the Siberian hamster, including a body weight decrease of up to 30%, increases neuronal activity in the dorsomedial region of the arcuate nucleus (dmpARC) assessed by electro physiological patch-clamping recording. Increased neuronal activity in short days is dependent on a photoperiod-driven down-regulation of H3 receptor expression and can be mimicked in long-day dmpARC neurons by the application of the H3 receptor antagonist, clobenproprit. Short-day activation of dmpARC neurons results in increased c-Fos expression. Tract tracing with the trans-synaptic retrograde tracer, pseudorabies virus, delivered into adipose tissue reveals a multisynaptic neuronal sympathetic outflow from dmpARC to white adipose tissue. These data strongly suggest that increased activity of dmpARC neurons, as a consequence of down-regulation of the histamine H3 receptor, contributes to the physiological adaptation of body weight regulation in seasonal photoperiod

Oulun läänin alueellinen jätesuunnitelma: Jätehuollon kehittämisohjelma vuosille 2008-2018

Oulun läänin alueellinen jätesuunnitelma on Kainuun ja Pohjois-Pohjanmaan ympäristökeskuksien yhteinen jätehuollon kehittämissuunnitelma. Sen laadinnassa on sovellettu SOVA-lain eli viranomaisten suunnitelmien ja ohjelmien ympäristövaikutusten arvioinnista annetun lain (200/2005) mukaista ympäristöarviointia, josta on laadittu ympäristöselostus. Käsillä olevassa Oulun läänin jätesuunnitelmassa on kolme osaa: jätehuollon nykytila (osa I), ympäristöselostus (osa II) ja suunnitelma (osa III). Jätesuunnitelmassa esitetään jätehuollon nykytila sekä tulevaisuuden kehittämistarpeet vuosille 2008 – 2018. Jätesuunnitelman taustatavoitteita ovat jätteen määrän vähentäminen (sisältäen jätteen synnyn ehkäisyn), jätteen hyötykäyttöasteen nostaminen, jätehuollon ympäristö- ja terveyshaittojen vähentäminen ja jätehuollon organisoinnin eko- ja kustannustehokkuus. Taustatavoitteiden mukaiselle kehitykselle on suunnitelmassa haettu kehittämisaskelia kahdeksalla painopistealueella. Ne ovat biohajoavan jätteen ohjaaminen pois kaatopaikoilta, jätteiden energiakäyttö, lietteiden jätehuolto mukaan lukien haja-asutuksen lietteet, energiantuotannon ja kaivosteollisuuden jätteet (tuhka, sivukivi, rikastushiekka), haja asutuksen jätehuollon palvelutaso ja kustannustehokkuus, roskaantumisen torjunta ja jätemaksujen kannustavuus sekä alueellinen yhteistyö keräilyssä, hyödyntämisessä ja käsittelyssä. Neljällä ensin mainitulla painopistealueilla on ympäristöarvioinnissa vertailtu erilaisia toteutusvaihtoehtoja. Vaihtoehtovertailussa edistämisen arvoisiksi vaihtoehdoiksi nousivat biohajoavien jätteiden syntypaikkalajittelun ja aineena hyödyntämisen (kompostointi, mädätys)kehittäminen, jätteiden energiakäytön osalta rinnakkaispolton edistäminen sille jätteelle, jonka muodostumista ei voida ehkäistä, ja jota ei voida kohtuullisin kustannuksin kierrättää, lietteiden osalta lannoitevalmistekäytön edistäminen ja tuhkan osalta sekä lannoitevalmiste- että maarakennuskäytön edistäminen. Sivukiven osalta jätteen synnyn ehkäisyn lisäksi edistetään sivukiven käyttöä maarakentamisessa. Jätteiden energiakäytön osalta myös muunlainen jätteiden poltto on mahdollista silloin, kun jätteiden synnyn ehkäisystä huolehditaan, hyödynnettävät jätelajit (mm. paperi, kartonki, biojäte) eivät kulkeudu polttoon, vaan ne hyödynnetään aineena, sekä polttoon menevien jätteiden määrä pidetään rajallisena

Supernova remnant S147 and its associated neutron star(s)

The supernova remnant S147 harbors the pulsar PSR J0538+2817 whose characteristic age is more than an order of magnitude greater than the kinematic age of the system (inferred from the angular offset of the pulsar from the geometric center of the supernova remnant and the pulsar proper motion). To reconcile this discrepancy we propose that PSR J0538+2817 could be the stellar remnant of the first supernova explosion in a massive binary system and therefore could be as old as its characteristic age. Our proposal implies that S147 is the diffuse remnant of the second supernova explosion (that disrupted the binary system) and that a much younger second neutron star (not necessarily manifesting itself as a radio pulsar) should be associated with S147. We use the existing observational data on the system to suggest that the progenitor of the supernova that formed S147 was a Wolf-Rayet star (so that the supernova explosion occurred within a wind bubble surrounded by a massive shell) and to constrain the parameters of the binary system. We also restrict the magnitude and direction of the kick velocity received by the young neutron star at birth and find that the kick vector should not strongly deviate from the orbital plane of the binary system.Comment: 9 pages, 5 figures, revised version accepted for publication in A&

Giant Pulses -- the Main Component of the Radio Emission of the Crab Pulsar

The paper presents an analysis of dual-polarization observations of the Crab pulsar obtained on the 64-m Kalyazin radio telescope at 600 MHz with a time resolution of 250 ns. A lower limit for the intensities of giant pulses is estimated by assuming that the pulsar radio emission in the main pulse and interpulse consists entirely of giant radio pulses; this yields estimates of 100 Jy and 35 Jy for the peak flux densities of giant pulses arising in the main pulse and interpulse, respectively. This assumes that the normal radio emission of the pulse occurs in the precursor pulse. In this case, the longitudes of the giant radio pulses relative to the profile of the normal radio emission turn out to be the same for the Crab pulsar and the millisecond pulsar B1937+21, namely, the giant pulses arise at the trailing edge of the profile of the normal radio emission. Analysis of the distribution of the degree of circular polarization for the giant pulses suggests that they can consist of a random mixture of nanopulses with 100% circular polarization of either sign, with, on average, hundreds of such nanopulses within a single giant pulse.Comment: 13 pages, 6 figures (originally published in Russian in Astronomicheskii Zhurnal, 2006, vol. 83, No. 1, pp. 62-69) translated by Denise Gabuzd

Profile instabilities of the millisecond pulsar PSR J1022+1001

We present evidence that the integrated profiles of some millisecond pulsars exhibit severe changes that are inconsistent with the moding phenomenon as known from slowly rotating pulsars. We study these profile instabilities in particular for PSR J1022+1001 and show that they occur smoothly, exhibiting longer time constants than those associated with moding. In addition, the profile changes of this pulsar seem to be associated with a relatively narrow-band variation of the pulse shape. Only parts of the integrated profile participate in this process which suggests that the origin of this phenomenon is intrinsic to the pulsar magnetosphere and unrelated to the interstellar medium. A polarization study rules out profile changes due to geometrical effects produced by any sort of precession. However, changes are observed in the circularly polarized radiation component. In total we identify four recycled pulsars which also exhibit instabilities in the total power or polarization profiles due to an unknown phenomenon (PSRs J1022+1001, J1730-2304, B1821-24, J2145-0750). The consequences for high precision pulsar timing are discussed in view of the standard assumption that the integrated profiles of millisecond pulsars are stable. As a result we present a new method to determine pulse times-of-arrival that involves an adjustment of relative component amplitudes of the template profile. Applying this method to PSR J1022+1001, we obtain an improved timing solution with a proper motion measurement of -17 \pm 2 mas/yr in ecliptic longitude. Assuming a distance to the pulsar as inferred from the dispersion measure this corresponds to an one-dimensional space velocity of 50 km/s.Comment: 29 pages, 12 figures, accepted for publication in Ap