523 research outputs found
Framework analysis: a worked example of a study exploring young peopleâs experiences of depression
Framework analysis is an approach to qualitative research which is being increasingly used across multiple disciplines, including psychology, social policy and nursing research. The stages of framework analysis have been described in published work, but the literature is lacking in articles describing how to conduct it in practice, particularly in the field of psychology, where researchers may be working as part of a team. Having used framework analysis on a study exploring adolescents' experiences of depression, we faced various challenges along the way and learned from experience how to use this approach to qualitative analysis. In this reflective article, we describe a worked example of using framework, which we hope will assist other researchers in deciding if this approach is suitable for their own research, and will provide guidance on how one might go about conducting framework analysis when working as part of a research team. We conclude that framework is a valuable contribution to qualitative methods in psychology, offering a pragmatic, flexible and rigorous approach to data analysis
Discovery of 59ms Pulsations from 1RXS J141256.0+792204 (Calvera)
We report on a multi-wavelength study of the compact object candidate 1RXS
J141256.0+792204 (Calvera). Calvera was observed in the X-rays with XMM/EPIC
twice for a total exposure time of ~50 ks. The source spectrum is thermal and
well reproduced by a two component model composed of either two hydrogen
atmosphere models, or two blackbodies (kT_1~ 55/150 eV, kT_2~ 80/250 eV,
respectively, as measured at infinity). Evidence was found for an absorption
feature at ~0.65 keV; no power-law high-energy tail is statistically required.
Using pn and MOS data we discovered pulsations in the X-ray emission at a
period P=59.2 ms. The detection is highly significant (> 11 sigma), and
unambiguously confirms the neutron star nature of Calvera. The pulse profile is
nearly sinusoidal, with a pulsed fraction of ~18%. We looked for the timing
signature of Calvera in the Fermi Large Area Telescope (LAT) database and found
a significant (~5 sigma) pulsed signal at a period coincident with the X-ray
value. The gamma-ray timing analysis yielded a tight upper limit on the period
derivative, dP/dt < 5E-18 s/s (dE_rot/dt <1E33 erg/s, B<5E10 G for magneto-
dipolar spin-down). Radio searches at 1.36 GHz with the 100-m Effelsberg radio
telescope yielded negative results, with a deep upper limit on the pulsed flux
of 0.05 mJy. Diffuse, soft (< 1 keV) X-ray emission about 13' west of the
Calvera position is present both in our pointed observations and in archive
ROSAT all-sky survey images, but is unlikely associated with the X-ray pulsar.
Its spectrum is compatible with an old supernova remnant (SNR); no evidence for
diffuse emission in the radio and optical bands was found. The most likely
interpretations are that Calvera is either a central compact object escaped
from a SNR or a mildly recycled pulsar; in both cases the source would be the
first ever member of the class detected at gamma-ray energies.Comment: 20 pages, 15 figures and 4 tables. Accepted for publication in MNRA
A Cosmic Census of Radio Pulsars with the SKA
The Square Kilometre Array (SKA) will make ground breaking discoveries in
pulsar science. In this chapter we outline the SKA surveys for new pulsars, as
well as how we will perform the necessary follow-up timing observations. The
SKA's wide field-of-view, high sensitivity, multi-beaming and sub-arraying
capabilities, coupled with advanced pulsar search backends, will result in the
discovery of a large population of pulsars. These will enable the SKA's pulsar
science goals (tests of General Relativity with pulsar binary systems,
investigating black hole theorems with pulsar-black hole binaries, and direct
detection of gravitational waves in a pulsar timing array). Using SKA1-MID and
SKA1-LOW we will survey the Milky Way to unprecedented depth, increasing the
number of known pulsars by more than an order of magnitude. SKA2 will
potentially find all the Galactic radio-emitting pulsars in the SKA sky which
are beamed in our direction. This will give a clear picture of the birth
properties of pulsars and of the gravitational potential, magnetic field
structure and interstellar matter content of the Galaxy. Targeted searches will
enable detection of exotic systems, such as the ~1000 pulsars we infer to be
closely orbiting Sgr A*, the supermassive black hole in the Galactic Centre. In
addition, the SKA's sensitivity will be sufficient to detect pulsars in local
group galaxies. To derive the spin characteristics of the discoveries we will
perform live searches, and use sub-arraying and dynamic scheduling to time
pulsars as soon as they are discovered, while simultaneously continuing survey
observations. The large projected number of discoveries suggests that we will
uncover currently unknown rare systems that can be exploited to push the
boundaries of our understanding of astrophysics and provide tools for testing
physics, as has been done by the pulsar community in the past.Comment: 20 pages, 7 figures, to be published in: "Advancing Astrophysics with
the Square Kilometre Array", Proceedings of Science, PoS(AASKA14)04
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Apportionment of primary and secondary organic aerosols in Southern California during the 2005 Study of Organic Aerosols in Riverside (SOAR-1)
Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionment techniques. The secondary organic aerosol (SOA) mass is estimated by elemental carbon and carbon monoxide tracer methods, water soluble organic carbon content, chemical mass balance of organic molecular markers, and positive matrix factorization of high-resolution aerosol mass spectrometer data. Estimates obtained from each of these methods indicate that the organic fraction in ambient aerosol is overwhelmingly secondary in nature during a period of several weeks with moderate ozone concentrations and that SOA is the single largest component of PM1 aerosol in Riverside. Average SOA/OA contributions of 70â90% were observed during midday periods, whereas minimum SOA contributions of ~45% were observed during peak morning traffic periods. These results are contrary to previous estimates of SOA throughout the Los Angeles Basin which reported that, other than during severe photochemical smog episodes, SOA was lower than primary OA. Possible reasons for these differences are discussed
A fast radio burst with a low dispersion measure
Fast radio bursts (FRBs) are millisecond pulses of radio emission of
seemingly extragalactic origin. More than 50 FRBs have now been detected, with
only one seen to repeat. Here we present a new FRB discovery, FRB 110214, which
was detected in the high latitude portion of the High Time Resolution Universe
South survey at the Parkes telescope. FRB 110214 has one of the lowest
dispersion measures of any known FRB (DM = 168.90.5 pc cm), and was
detected in two beams of the Parkes multi-beam receiver. A triangulation of the
burst origin on the sky identified three possible regions in the beam pattern
where it may have originated, all in sidelobes of the primary detection beam.
Depending on the true location of the burst the intrinsic fluence is estimated
to fall in the range of 50 -- 2000 Jy ms, making FRB 110214 one of the
highest-fluence FRBs detected with the Parkes telescope. No repeating pulses
were seen in almost 100 hours of follow-up observations with the Parkes
telescope down to a limiting fluence of 0.3 Jy ms for a 2-ms pulse. Similar
low-DM, ultra-bright FRBs may be detected in telescope sidelobes in the future,
making careful modeling of multi-beam instrument beam patterns of utmost
importance for upcoming FRB surveys.Comment: 8 pages, 3 figures, accepted for publication in MNRA
Pulsar Searches with the SKA
The Square Kilometre Array will be an amazing instrument for pulsar
astronomy. While the full SKA will be sensitive enough to detect all pulsars in
the Galaxy visible from Earth, already with SKA1, pulsar searches will discover
enough pulsars to increase the currently known population by a factor of four,
no doubt including a range of amazing unknown sources. Real time processing is
needed to deal with the 60 PB of pulsar search data collected per day, using a
signal processing pipeline required to perform more than 10 POps. Here we
present the suggested design of the pulsar search engine for the SKA and
discuss challenges and solutions to the pulsar search venture.Comment: 4 pages, 1 figure. To be published in Proceedings of IAU Symposium
337: Pulsar Astrophysics - The Next 50 Year
Beyond a diagnosis: the experience of depression among clinically-referred adolescents
Policy-makers have identified an urgent need to improve our ability to detect and diagnose depression in adolescents. This study aims to explore the lived experience of depression in clinically referred adolescents. 77 adolescents, aged between 11 and 17 with moderate to severed depression, were interviewed as part of a randomised controlled trial, using the Expectations of Therapy interview. Data were analysed qualitatively using framework analysis, with a focus on how the adolescents spoke about their depression. The study identified five themes: 1) Misery, despair and tears; 2) Anger and violence towards self and others; 3) A bleak view of everything; 4)Isolation and cutting off from the world; and 5) The impact on education. Researchers and policy-makers need to develop an understanding of depression grounded in the experiences of adolescents to improve detection and diagnosis of depression
Unusual glitch activity in the RRAT J1819-1458: an exhausted magnetar?
We present an analysis of regular timing observations of the
high-magnetic-field Rotating Radio Transient (RRAT) J18191458 obtained using
the 64-m Parkes and 76-m Lovell radio telescopes over the past five years.
During this time, the RRAT has suffered two significant glitches with
fractional frequency changes of and .
Glitches of this magnitude are a phenomenon displayed by both radio pulsars and
magnetars. However, the behaviour of J18191458 following these glitches is
quite different to that which follows glitches in other neutron stars, since
the glitch activity resulted in a significant long-term net decrease in the
slow-down rate. If such glitches occur every 30 years, the spin-down rate, and
by inference the magnetic dipole moment, will drop to zero on a timescale of a
few thousand years. There are also significant increases in the rate of pulse
detection and in the radio pulse energy immediately following the glitches.Comment: accepted for publication in MNRAS, 7 pages, 7 figures, 1 tabl
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