Timing of Five PALFA-Discovered Millisecond Pulsars

We report the discovery and timing results for five millisecond pulsars (MSPs) from the Arecibo PALFA survey: PSRs J1906+0055, J1914+0659, J1933+1726, J1938+2516, and J1957+2516. Timing observations of the five pulsars were conducted with the Arecibo and Lovell telescopes for time spans ranging from 1.5 to 3.3 years. All of the MSPs except one (PSR J1914+0659) are in binary systems with low eccentricities. PSR J1957+2516 is likely a redback pulsar, with a $\sim 0.1\,{M}_{\odot }$ companion and possible eclipses that last ~10% of the orbit. The position of PSR J1957+2516 is also coincident with a near-infrared source. All five MSPs are distant ($\gt 3.1$ kpc) as determined from their dispersion measures, and none of them show evidence of γ-ray pulsations in a fold of Fermi Gamma-Ray Space Telescope data. These five MSPs bring the total number of MSPs discovered by the PALFA survey to 26 and further demonstrate the power of this survey in finding distant, highly dispersed MSPs deep in the Galactic plane

Timing of 29 Pulsars Discovered in the PALFA Survey

We report on the discovery and timing observations of 29 distant long-period pulsars found in the ongoing Arecibo L-band Feed Array pulsar survey. Following discovery with the Arecibo Telescope, confirmation and timing observations of these pulsars over several years at Jodrell Bank Observatory have yielded high-precision positions and measurements of rotation and radiation properties. We have used multi-frequency data to measure the interstellar scattering properties of some of these pulsars. Most of the pulsars have properties that mirror those of the previously known pulsar population, although four show some notable characteristics. PSRs J1907+0631 and J1925+1720 are young and are associated with supernova remnants or plerionic nebulae: J1907+0631 lies close to the center of SNR G40.5−0.5, while J1925+1720 is coincident with a high-energy Fermi γ-ray source. One pulsar, J1932+1500, is in a surprisingly eccentric, 199 day binary orbit with a companion having a minimum mass of 0.33 M⊙. Several of the sources exhibit timing noise, and two, PSRs J0611+1436 and J1907+0631, have both suffered large glitches, but with very different post-glitch rotation properties. In particular, the rotational period of PSR J0611+1436 will not recover to its pre-glitch value for about 12 years, a far greater recovery timescale than seen following any other large glitches

Einstein@Home Discovery of a PALFA Millisecond Pulsar in an Eccentric Binary Orbit

We report the discovery of the millisecond pulsar (MSP) PSR J1950+2414 (P = 4.3 ms) in a binary system with an eccentric (e = 0.08) 22 day orbit in Pulsar Arecibo L-band Feed Array survey observations with the Arecibo telescope. Its companion star has a median mass of 0.3M(circle dot) and is most likely a white dwarf (WD). Fully recycled MSPs like this one are thought to be old neutron stars spun-up by mass transfer from a companion star. This process should circularize the orbit, as is observed for the vast majority of binary MSPs, which predominantly have orbital eccentricities e <0.001. However, four recently discovered binary MSPs have orbits with 0. 027 <e <0.44; PSR J1950+2414 is the fifth such system to be discovered. The upper limits for its intrinsic spin period derivative and inferred surface magnetic field strength are comparable to those of the general MSP population. The large eccentricities are incompatible with the predictions of the standard recycling scenario: something unusual happened during their evolution. Proposed scenarios are (a) initial evolution of the pulsar in a triple system which became dynamically unstable, (b) origin in an exchange encounter in an environment with high stellar density, (c) rotationally delayed accretion-induced collapse of a super-Chandrasekhar WD, and (d) dynamical interaction of the binary with a circumbinary disk. We compare the properties of all five known eccentric MSPs with the predictions of these formation channels. Future measurements of the masses and proper motion might allow us to firmly exclude some of the proposed formation scenarios

A borderland Confederate.

"Civil War diaries and letters."Bibliographical footnotes.Mode of access: Internet

Fatores preditivos para evolução insatisfatória de quadris instáveis na paralisia cerebral submetidos à reconstrução articular Predictive factors for unsatisfactory evolution of unstable hips in brain palsy submitted to joint reconstruction

OBJETIVO: Avaliar os possíveis fatores prognósticos que indicariam a evolução insatisfatória do tratamento da subluxação e/ou luxação espástica do quadril nos pacientes portadores de Paralisia Cerebral submetidos à reconstrução cirúrgica, mediante liberação de partes moles, adutores e íliopsoas, e a osteotomia pélvica de Dega associada a osteotomia femoral subtrocantérica, varizante de rotação externa e de encurtamento. CASUÍSTICA E MÉTODOS: Foram analisados retrospectivamente de Outubro de 1994 a Agosto de 2005, clínica e radiograficamente 58 pacientes (78 quadris) com subluxação/luxação espástica submetidos à reconstrução cirúrgica. O seguimento mínimo foi de 12 meses e o médio de 53,6 meses. Os quadris foram classificados em satisfatórios e insatisfatórios de acordo com a análise do índice acetabular (IA) e índice de Reimers (IR) pós-operatório final. Foram analisadas estatisticamente as variáveis: idade do paciente na época da cirurgia, tempo de seguimento pós-operatório e os parâmetros radiográficos IA, IR, ângulo cérvico-diafisário (CD) nos períodos pré-operatório, pós-operatório imediato e final. RESULTADOS: Dos 78 quadris analisados, 13 foram classificados como insatisfatórios por apresentarem IA pós-operatório final maior ou igual a 20 graus e IR pós-operatório final maior ou igual 25% e após análise estatística dos dados foi observada significância apenas no IA pós-operatório imediato, IA pós-operatório final, IR pós-operatório final e CD pós-operatório final. CONCLUSÃO: Não há variável que possa predizer evolução insatisfatória do pós-operatório da reconstrução articular nos casos de sub e/ou luxação espástica do quadril, porém evidenciou-se que maior empenho deve ser aplicado na correção do índice acetabular no ato cirúrgico.<br>OBJECTIVE: To evaluate potential prognostic factors that would indicate an unsatisfactory treatment evolution of hip sub-dislocation and/or spastic dislocation in patients with Brain Palsy submitted to surgical reconstruction, upon soft parts, adductors and iliopsoas release, and Dega’s pelvic osteotomy combined to outer-rotation and shortening varusing sub-trochanteric femoral osteotomy. CASE SERIES AND METHODS: 58 patients (78 hips) with sub-dislocation/ spastic dislocation submitted to surgical reconstruction were retrospectively assessed, both clinically and by X-ray studies, from October 1994 to August 2005. The minimum follow-up time was 12 months and the average was 53.6 months. Hips were classified into satisfactory and unsatisfactory according to the analysis of late postoperative acetabular index (AI) and Reimers index (RI). The following variables were statistically analyzed: patient’s age at surgery time, postoperative follow-up period, and AI, RI X-ray parameters, cervicodiaphyseal angle (CD) at preoperative, early postoperative and late postoperative periods. RESULTS: From the 78 hips assessed, 13 were classified as unsatisfactory because they presented a late postoperative AI higher or equal to 20 degrees, and a late postoperative RI higher or equal to 25%, and, after the statistical analysis of data, significance was reported only at early postoperative AI, late postoperative AI, late postoperative RI, and late postoperative CD. CONCLUSION: There is no variable that can predict an unsatisfactory postoperative evolution on joint reconstruction in cases of hip sub-dislocation and/ or spastic dislocation, but it was evidenced that stronger efforts must be employed when correcting the acetabular index during a surgical procedure