3,112 research outputs found
The XMM-Newton Detection of Diffuse Inverse Compton X-rays from Lobes of the FR-II Radio Galaxy 3C98
The XMM-Newton observation of the nearby FR-II radio galaxy 3C 98 is
reported. In two exposures on the target, faint diffuse X-ray emission
associated with the radio lobes was significantly detected, together with a
bright X-ray active nucleus, of which the 2 -- 10 keV intrinsic luminosity is
(4 -- 8) \times 10^{42} erg s-1. The EPIC spectra of the northern and southern
lobes are reproduced by a single power law model modified by the Galactic
absorption, with a photon index of 2.2-0.5+0.6 and 1.7-0.6+0.7 respectively.
These indices are consistent with that of the radio synchrotron spectrum, 1.73
+- 0.01 The luminosity of the northern and southern lobes are measured to be
8.3-2.6+3.3 \times 10^{40} erg s-1 and 9.2-4.3+5.7 \times 10^{40} erg s-1,
respectively, in the 0.7 -- 7 keV range. The diffuse X-ray emission is
interpreted as an inverse-Compton emission, produced when the
synchrotron-emitting energetic electrons in the lobes scatter off the cosmic
microwave background photons. The magnetic field in the lobes is calculated to
be about 1.7 \mu G, which is about 2.5 times lower than the value estimated
under the minimum energy condition. The energy density of the electrons is
inferred to exceed that in the magnetic fields by a factor of 40 -- 50.Comment: 23 pages, 7 figures. Accepted for publication in the Astrophysical
Journa
A quantification of the physiological demands of the army emergency responder in the Australian Army
The Australian Defence Force is reviewing the physical demands of all employment categories in the Australian Army to establish valid and legally defensible assessments. The current assessments, performed in physical training attire, are not specific to job demands. Moreover, the fitness standards decrease based on age and are lower for females, and as job requirements are constant, these assessments are counterintuitive. With regard to the Army Emergency Responder employment category, tasks of physical demand in the present study were selected through consultation with subject-matter experts. Participants consisted of 10 qualified Army Emergency Responder soldiers and three noncareer firefighters under instruction. Real-life firefighting scenarios were witnessed by researchers and helped form task simulations allowing measurement of heart rate and oxygen consumption. Peak oxygen consumption ranged from 21.8 ± 3.8 to 40.0 ± 3.4 mL kg−1 min−1 during cutting activities and a search and rescue task, respectively, representing values similar to or higher than the current entry standards. Manual handling tasks were also assessed, with the heaviest measured being two soldiers lifting a 37.7-kg Utility Trunk to 150 cm. The findings provide a quantitative assessment of the physiological demands of Army Emergency Responders, and highlight the need for change in current fitness assessments
Chandra detection of the radio and optical double hot spot of 3C 351
In this letter we report a Chandra X-ray detection of the double northern hot
spot of the radio quasar 3C 351. The hot spot has also been observed in the
optical with the Hubble Space Telescope (R-band) and with the 3.5m. Telescopio
Nazionale Galileo (B-band). The radio-to-optical and X-ray spectra are
interpreted as the results of the synchrotron and synchrotron-self-Compton
(SSC) mechanisms, respectively, with hot-spot magnetic field strengths ~3 times
smaller than the equipartition values. In the framework of shock acceleration
theory, we show that the requirement for such a relatively small field strength
is in agreement with the fitted synchrotron spectral models and with the sizes
of the hot spots. Finally, we show that the combination of a lower magnetic
field strength with the high frequencies of the synchrotron cut-off in the
fitted synchrotron spectra provides strong evidence for electron acceleration
in the hot spots.Comment: 16 pag. + 2 .PS figures (fig.2 color), ApJ Letter in pres
A Chandra detection of diffuse hard X-ray emission associated with the lobes of the radio galaxy 3C 452
An 80 ksec Chandra ACIS observation of the radio galaxy 3C 452 is reported. A
diffuse X-ray emission associated with the lobes has been detected with high
statistical significance, together with the X-ray nucleus of the host galaxy.
The 0.5--5 keV ACIS spectrum of the diffuse emission is described by a
two-component model, consisting of a soft thermal plasma emission from the host
galaxy halo and a hard non-thermal power-law component. The hard component is
ascribed to the inverse Comptonization of cosmic microwave background photons
by the synchrotron emitting electrons in the lobes, because its spectral energy
index, 0.68+-0.28, is consistent with the radio synchrotron index, 0.78. These
results reveal a significant electron dominance in the lobes. The electrons are
inferred to have a relatively uniform distribution, while the magnetic field is
compressed toward the lobe periphery.Comment: 4 figures, 2 tables, Accepted by ApJL (to appear in the December 1
issue
Multifrequency VLA observations of the FR I radio galaxy 3C 31: morphology, spectrum and magnetic field
We present high-quality VLA images of the FR I radio galaxy 3C 31 in the
frequency range 1365 to 8440 MHz with angular resolutions from 0.25 to 40
arcsec. Our new images reveal complex, well resolved filamentary substructure
in the radio jets and tails. We also use these images to explore the spectral
structure of 3C 31 on large and small scales. We infer the apparent magnetic
field structure by correcting for Faraday rotation. Some of the intensity
substructure in the jets is clearly related to structure in their apparent
magnetic field: there are arcs of emission where the degree of linear
polarization increases, with the apparent magnetic field parallel to the ridges
of the arcs. The spectral indices are significantly steeper (0.62) within 7
arcsec of the nucleus than between 7 and 50 arcsec (0.52 - 0.57). The spectra
of the jet edges are also slightly flatter than the average for their
surroundings. At larger distances, the jets are clearly delimited from
surrounding larger-scale emission both by their flatter radio spectra and by
sharp brightness gradients. The spectral index of 0.62 in the first 7 arcsec of
3C 31's jets is very close to that found in other FR I galaxies where their
jets first brighten in the radio and where X-ray synchrotron emission is most
prominent. Farther from the nucleus, where the spectra flatten, X-ray emission
is fainter relative to the radio. The brightest X-ray emission from FR I jets
is therefore not associated with the flattest radio spectra, but with a
particle-acceleration process whose characteristic energy index is 2.24. The
spectral flattening with distance from the nucleus occurs where our
relativistic jet models require deceleration, and the flatter-spectra at the
jet edges may be associated with transverse velocity shear. (Slightly abridged)Comment: 17 pages, 13 figures, accepted for publication in MNRA
The Golden Channel at a Neutrino Factory revisited: improved sensitivities from a Magnetised Iron Neutrino Detector
This paper describes the performance and sensitivity to neutrino mixing
parameters of a Magnetised Iron Neutrino Detector (MIND) at a Neutrino Factory
with a neutrino beam created from the decay of 10 GeV muons. Specifically, it
is concerned with the ability of such a detector to detect muons of the
opposite sign to those stored (wrong-sign muons) while suppressing
contamination of the signal from the interactions of other neutrino species in
the beam. A new more realistic simulation and analysis, which improves the
efficiency of this detector at low energies, has been developed using the GENIE
neutrino event generator and the GEANT4 simulation toolkit. Low energy neutrino
events down to 1 GeV were selected, while reducing backgrounds to the
level. Signal efficiency plateaus of ~60% for and ~70% for
events were achieved starting at ~5 GeV. Contamination from the
oscillation channel was studied for the first
time and was found to be at the level between 1% and 4%. Full response matrices
are supplied for all the signal and background channels from 1 GeV to 10 GeV.
The sensitivity of an experiment involving a MIND detector of 100 ktonnes at
2000 km from the Neutrino Factory is calculated for the case of . For this value of , the accuracy in the
measurement of the CP violating phase is estimated to be , depending on the value of ,
the CP coverage at is 85% and the mass hierarchy would be determined
with better than level for all values of
Phosphoproteins and protein-kinase activity in isolated envelopes of pea (Pisum sativum L.) chloroplasts
A protein kinase was found in envelope membranes of purified pea (Pisum sativum L.) chloroplasts. Separation of the two envelope membranes showed that most of the enzyme activity was localized in the outer envelope. The kinase was activated by Mg2+ and inhibited by ADP and pyrophosphate. It showed no response to changes in pH in the physiological range (pH 7-8) or conventional protein substrates. Up to ten phosphorylated proteins could be detected in the envelope-membrane fraction. The molecular weights of these proteins, as determined by polyacrylamide-gel electrophoresis were: two proteins higher than 145 kDa, 97, 86, 62, 55, 46, 34 and 14 kDa. The 86-kDa band being the most pronounced. Experiments with separated inner and outer envelopes showed that most labeled proteins are also localized in the outer-envelope fraction. The results indicate a major function of the outer envelope in the communication between the chloroplast and the parent cell
Beyond the call of duty: A Qualitative study into the experiences of family members acting as a Nearest Relative in Mental Health Act assessments
Abstract Research shows that tensions between family carers and professionals become acute where the issue of compulsory admission to hospital is at stake. In England and Wales, a specific family member is appointed to safeguard the interests of a person assessed under the Mental Health Act 1983. This currently occurs through the Nearest Relative (NR) role. The Government is proposing to replace this with a Nominated Person role, chosen by the service user. Drawing on the concept of carer burden, this study reports on the views of nineteen NRs in England to discover their experiences of being involved in a Mental Health Act assessment. Participants identified that they undertook the role due to a sense of duty. Their experiences were mixed with participants highlighting both feelings of distress during the assessment and feelings of relief once their relative had been detained. Participants reported feeling conflicted when their relative was detained and feelings of frustration towards mental health services. The findings have implications for proposals to reform the Mental Health Act 1983. They show that education and support programmes should be created for NRs/Nominated Persons and that research is needed to assess whether such support is effective at reducing carer burden.</jats:p
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