On the Unpulsed Radio Emission from J0737-3039

The double pulsar system J0737-3039 appears associated with a continuous radio emission, nearly three times stronger than that of the two pulsars together. If such an emission comes from a tranparent cloud its spatial extent (> 10^13 cm) should be substantially larger than the orbital separation. Assuming homogeneity and equipartition, the cloud magnetic field is 0.03 G and the electron characteristic energy ~ 60 MeV. This is consistent with supposing that relativistic electrons produced in the shock formed by the interaction of the more luminous pulsar wind with the magnetosphere of the companion flow away filling a larger volume. Alternatively, the unpulsed emission may directly come from the bow shock if some kind of coherent mechanism is at work. Possible observational signatures that can dicriminate between the two pictures are shortly discussed.Comment: 4 pages, no figures, accepted for publication in A&A (Letters

Radio Emission Signatures in the Crab Pulsar

Our high time resolution observations of individual pulses from the Crab pulsar show that both the time and frequency signatures of the interpulse are distinctly different from those of the main pulse. Main pulses can occasionally be resolved into short-lived, relatively narrow-band nanoshots. We believe these nanoshots are produced by soliton collapse in strong plasma turbulence. Interpulses at centimeter wavelengths are very different. Their dynamic spectrum contains regular, microsecond-long emission bands. We have detected these bands, proportionately spaced in frequency, from 4.5 to 10.5 GHz. The bands cannot easily be explained by any current theory of pulsar radio emission; we speculate on possible new models.Comment: 26 pages, 10 figures, to appear in Ap

Parents' expressed emotion and mood, rather than their physical disability are associated with adolescent adjustment. A longitudinal study of families with a parent with multiple sclerosis

Objective. This study investigated the impact of the severity of parental multiple sclerosis, parents’ expressed emotion and psychological well-being on offspring’s psychological difficulties. Design: A longitudinal study including baseline and 6-month follow-up data collected from parents and children. Subjects: Adolescents (n=75), their parents with multiple sclerosis (n=56) and the partner without multiple sclerosis (n=40) Main measures: Parents completed the Hospital Anxiety and Depression Scale and the Five Minutes Speech Sample, a standardised interview of expressed emotion towards their child. Parents with multiple sclerosis also completed the Expanded Disability Status Scale, a measure of illness severity. Adolescents completed the Strength and Difficulties Questionnaire, a self-report measure of psychological difficulties. Results: Higher depression scores of the parents with multiple sclerosis at baseline correlated with increased adolescents’ internalising symptoms at 6-month follow-up (γdep=0.31, p=.004). Higher expressed emotion scores of parents with multiple sclerosis at baseline were associated with increased adolescent externalising symptoms at 6-month follow-up (γEE=4.35, p=.052). There was no direct effect of severity, duration or type of multiple sclerosis on adolescents’ adjustment at baseline or follow-up. Conclusions: Emotional distress and expressed emotion in parents with multiple sclerosis, rather than the severity and type of multiple sclerosis had an impact on adolescents’ psychological difficulties

A VLA Search for the Geminga Pulsar: A Bayesian Limit on a Scintillating Source

We derive an upper limit of 3 mJy (95% confidence) for the flux density at 317 MHz of the Geminga pulsar (J0633+1746). Our results are based on 7 hours of fast-sampled VLA data, which we averaged synchronously with the pulse period using a period model based on CGRO/EGRET gamma-ray data. Our limit accounts for the fact that this pulsar is most likely subject to interstellar scintillations on a timescale much shorter than our observing span. Our Bayesian method is quite general and can be applied to calculate the fluxes of other scintillated sources. We also present a Bayesian technique for calculating the flux in a pulsed signal of unknown width and phase. Comparing our upper limit of 3 mJy with the quoted flux density of Geminga at 102 MHz, we calculate a lower limit to its spectral index of 2.7. We discuss some possible reasons for Geminga's weakness at radio wavelengths, and the likelihood that many of the unidentified EGRET sources are also radio-quiet or radio-weak Geminga-like pulsars.Comment: 27 pages, including figures. Published in Ap

Measurement of Orbital Decay in the Double Neutron Star Binary PSR B2127+11C

We report the direct measurement of orbital period decay in the double neutron star pulsar system PSR B2127+11C in the globular cluster M15 at the rate of $(-3.95 \pm 0.13) \times 10^{-12}$, consistent with the prediction of general relativity at the $\sim 3$ level. We find the pulsar mass to be $m_p = (1.358 \pm 0.010) M_\odot$ and the companion mass $m_c = (1.354 \pm 0.010) M_\odot$. We also report long-term pulse timing results for the pulsars PSR B2127+11A and PSR B2127+11B, including confirmation of the cluster proper motion.Comment: 12 pages, 4 figures, accepted for publication in ApJ

Improved flux limits for neutrinos with energies above 1022^{22} eV from observations with the Westerbork Synthesis Radio Telescope

Particle cascades initiated by ultra-high energy (UHE) neutrinos in the lunar regolith will emit an electromagnetic pulse with a time duration of the order of nano seconds through a process known as the Askaryan effect. It has been shown that in an observing window around 150 MHz there is a maximum chance for detecting this radiation with radio telescopes commonly used in astronomy. In 50 hours of observation time with the Westerbork Synthesis Radio Telescope array we have set a new limit on the flux of neutrinos, summed over all flavors, with energies in excess of $4\times10^{22}$ eV.Comment: Submitted to Phys. Rev. Let

LUNASKA experiments using the Australia Telescope Compact Array to search for ultra-high energy neutrinos and develop technology for the lunar Cherenkov technique

We describe the design, performance, sensitivity and results of our recent experiments using the Australia Telescope Compact Array (ATCA) for lunar Cherenkov observations with a very wide (600 MHz) bandwidth and nanosecond timing, including a limit on an isotropic neutrino flux. We also make a first estimate of the effects of small-scale surface roughness on the effective experimental aperture, finding that contrary to expectations, such roughness will act to increase the detectability of near-surface events over the neutrino energy-range at which our experiment is most sensitive (though distortions to the time-domain pulse profile may make identification more difficult). The aim of our "Lunar UHE Neutrino Astrophysics using the Square Kilometer Array" (LUNASKA) project is to develop the lunar Cherenkov technique of using terrestrial radio telescope arrays for ultra-high energy (UHE) cosmic ray (CR) and neutrino detection, and in particular to prepare for using the Square Kilometer Array (SKA) and its path-finders such as the Australian SKA Pathfinder (ASKAP) and the Low Frequency Array (LOFAR) for lunar Cherenkov experiments.Comment: 27 pages, 18 figures, 4 tables

The psychological impact of human papillomavirus testing in women with borderline or mildly dyskaryotic cervical smear test results: 6-month follow-up

State anxiety (S-STAI-6), distress (GHQ-12), concern and quality of life (EuroQoL-EQ-5D) 6 months after human papillomavirus (HPV) testing in women with borderline or mildly dyskaryotic smear test results were assessed based on a prospective questionnaire study, with 6-month follow-up after the smear test result. Two centres participated in an English pilot study of HPV testing. Participants included two groups of women receiving abnormal smear test results: (tested for HPV and found to be (a) HPV positive (n=369) or (b) HPV negative (n=252)) and two groups not tested for HPV (those receiving (c) abnormal smear test results (n=102) or (d) normal smear test results (n=288)). There were no differences in anxiety, distress or health-related quality of life between the four study groups at 6 months. Levels of concern about the smear test result remained elevated in all groups receiving an abnormal smear test result, and were highest in the group untested for HPV. Predictors of concern across all groups receiving an abnormal smear test were perceived risk of developing cancer, being HPV positive or untested for HPV, sexual health worries and the smear being a woman's first smear test. The raised anxiety and distress observed in women immediately after being informed of an abnormal smear test result and that they are HPV positive was no longer evident at 6 months. Concern about the smear test result was however still raised in these women and those who tested negative for HPV, and particularly among those who did not undergo HPV testing

Cherenkov radio pulses from electromagnetic showers in the time-domain

The electric field of the Cherenkov radio pulse produced by a single charged particle track in a dielectric medium is derived from first principles. An algorithm is developed to obtain the pulse in the time domain for numerical calculations. The algorithm is implemented in a Monte Carlo simulation of electromagnetic showers in dense media (specifically designed for coherent radio emission applications) as might be induced by interactions of ultra-high energy neutrinos. The coherent Cherenkov radio emission produced by such showers is obtained simultaneously both in the time and frequency domains. A consistency check performed by Fourier-transforming the pulse in time and comparing it to the frequency spectrum obtained directly in the simulations yields, as expected, fully consistent results. The reversal of the time structure inside the Cherenkov cone and the signs of the corresponding pulses are addressed in detail. The results, besides testing algorithms used for reference calculations in the frequency domain, shed new light into the properties of the radio pulse in the time domain. The shape of the pulse in the time domain is directly related to the depth development of the excess charge in the shower and its width to the observation angle with respect to the Cherenkov direction. This information can be of great practical importance for interpreting actual data.Comment: 10 pages, 4 figure