Interception and Offshore Processing of Asylum Seekers: The International Law Dimensions

For decades the international community has conducted a delicate and politically charged balancing act trying to reconcile the inexorable increase in refugees-and the need to find permanent homes for them with the fundamental right of all countries to have secure frontiers. While the notion of non-refoulement remains fundamental to the treatment of asylum seekers, their rights vis A vis the states in which they seek asylum are significantly circumscribed by their alien status. States have a right to control entry to their territories. In the development of asylum law and policy, the central difficulty for states, and indeed the international community, is how to construct an appropriate balance between the urgent humanitarian demands to protect those who are genuinely in need of asylum, and the exclusion of those who do not qualify for humanitarian protection

Accreting magnetars: a new type of high-mass X-ray binaries?

The discovery of very slow pulsations (Pspin=5560s) has solved the long-standing question of the nature of the compact object in the high-mass X-ray binary 4U 2206+54 but has posed new ones. According to spin evolutionary models in close binary systems, such slow pulsations require a neutron star magnetic field strength larger that the quantum critical value, suggesting the presence of a magnetar. We present the first XMM-Newton observations of 4U 2206+54 and investigate its spin evolution. We find that the observed spin-down rate agrees with the magnetar scenario. We analyse ISGRI/INTEGRAL observations of 4U 2206+54 to search for the previously suggested cyclotron resonance scattering feature at ~30 keV. We do not find a clear indication of the presence of the line, although certain spectra display shallow dips, not always at 30 keV. The association of these dips with a cyclotron line is very dubious because of its apparent transient nature. We also investigate the energy spectrum of 4U 2206+54 in the energy range 0.3-10 keV with unprecedented detail and report for the first time the detection of very weak 6.5 keV fluorescence iron lines. The photoelectric absorption is consistent with the interstellar value, indicating very small amount of local matter, which would explain the weakness of the florescence lines. The lack of matter locally to the source may be the consequence of the relatively large orbital separation of the two components of the binary. The wind would be too tenuous in the vicinity of the neutron star.Comment: accepted for publication in MNRA

A simple derivation of Kepler's laws without solving differential equations

Proceeding like Newton with a discrete time approach of motion and a geometrical representation of velocity and acceleration, we obtain Kepler's laws without solving differential equations. The difficult part of Newton's work, when it calls for non trivial properties of ellipses, is avoided by the introduction of polar coordinates. Then a simple reconsideration of Newton's figure naturally leads to en explicit expression of the velocity and to the equation of the trajectory. This derivation, which can be fully apprehended by beginners at university (or even before) can be considered as a first application of mechanical concepts to a physical problem of great historical and pedagogical interest

Wind accretion in the massive X-ray binary 4U 2206+54: abnormally slow wind and a moderately eccentric orbit

Massive X-ray binaries are usually classified depending on the properties of the donor star in classical, supergiant and Be X-ray binaries. The massive X-ray binary 4U 2206+54 does not fit in any of these groups, and deserves a detailed study to understand how the transfer of matter and the accretion on to the compact object take place. To this end we study an IUE spectrum of the donor and obtain a wind terminal velocity (v_inf) of ~350 km/s, which is abnormally slow for its spectral type. We also analyse here more than 9 years of available RXTE/ASM data. We study the long-term X-ray variability of the source and find it to be similar to that observed in the wind-fed supergiant system Vela X-1, reinforcing the idea that 4U 2206+54 is also a wind-fed system. We find a quasi-period decreasing from ~270 to ~130 d, noticed in previous works but never studied in detail. We discuss possible scenarios and conclude that long-term quasi-periodic variations in the mass-loss rate of the primary are probably driving such variability in the measured X-ray flux. We obtain an improved orbital period of 9.5591 d with maximum X-ray flux at MJD 51856.6. Our study of the orbital X-ray variability in the context of wind accretion suggests a moderate eccentricity around 0.15. Moreover, the low value of v_inf solves the long-standing problem of the relatively high X-ray luminosity for the unevolved nature of the donor, BD +53 2790, which is probably an O9.5 V star. We note that changes in v_inf and/or the mass-loss rate of the primary alone cannot explain the diferent patterns displayed by the orbital X-ray variability. We finally emphasize that 4U 2206+54, together with LS 5039, could be part of a new population of wind-fed HMXBs with main sequence donors, the natural progenitors of supergiant X-ray binaries. (Abridged)Comment: 12 pages, 9 figures; to appear in A&A; corrected typos, updated references; matches published versio

The Community Nurse in Australia. Who are they? A rapid systematic review.

AimTo profile the community nurse in Australia.BackgroundThe need for nurses in the community health care sector is increasing in response to shorter hospital stays, an ageing population and chronic disease. The increase in demand has not been followed by appropriate workforce planning, leading to structural issues and lack of qualified nursing workforce in the community sector.EvaluationMEDLINE and ProQuest Public Health and grey literature were searched for records published between 2010-2020 relative to the profile of the community nurse in Australia. Twenty-five records (21 publications, two databases and two reports) were included in the review. Abstracted data followed the principles of workforce planning, and included demographics, qualifications and roles.Key issuesInconsistent definitions, self-reported data and a focus on practice nurses have contributed to data irregularities. Little is known about the specific aspects of community nursing work.ConclusionA lack of concrete data has over-shadowed a community nursing workforce crisis with implications for patients' health and safety across the lifespan.Implications for nursing managementThere is urgent need for nurse managers globally to refocus nursing recruitment to the community sector to maintain quality and ensure sustainability of the nursing workforce

Studying the accretion geometry of EXO 2030+375 at luminosities close to the propeller regime

The Be X-ray binary EXO 2030+375 was in an extended low luminosity state during most of 2016. We observed this state with NuSTAR and Swift, supported by INTEGRAL observations as well as optical spectroscopy with the NOT. We present a comprehensive spectral and timing analysis of these data here to study the accretion geometry and investigate a possible onset of the propeller effect. The H-alpha data show that the circumstellar disk of the Be-star is still present. We measure equivalent widths similar to values found during more active phases in the past, indicating that the low-luminosity state is not simply triggered by a smaller Be disk. The NuSTAR data, taken at a 3-78 keV luminosity of ~6.8e35 erg/s (for a distance of 7.1 kpc), are well described by standard accreting pulsar models, such as an absorbed power-law with a high-energy cutoff. We find that pulsations are still clearly visible at these luminosities, indicating that accretion is continuing despite the very low mass transfer rate. In phase-resolved spectroscopy we find a peculiar variation of the photon index from ~1.5 to ~2.5 over only about 3% of the rotational period. This variation is similar to that observed with XMM-Newton at much higher luminosities. It may be connected to the accretion column passing through our line of sight. With Swift/XRT we observe luminosities as low as 1e34 erg/s during which the data quality did not allow us to search for pulsations, but the spectrum is much softer and well described by either a blackbody or soft power-law continuum. This softer spectrum might be due to the fact that accretion has been stopped by the propeller effect and we only observe the neutron star surface cooling.Comment: 11 pages, 6 figures, accepted for publication in A&A (v2 including language edits

First observations of the X-ray transient EXO 2030+375 with IBIS/ISGRI

We present a first INTEGRAL observation of the 42s transient X-ray pulsar EXO 2030+375 with IBIS/ISGRI. The source was detected during Cyg X-1 observations in December 2002. We analyzed observations during the outburst period from 9 to 21 December 2002 with a total exposure time of ~770 kiloseconds. EXO 2030+375 was almost always detected during single ~30 minute exposures in the 18-45 energy bands. The source light curve shows the characteristic outburst shape observed in this source.Comment: 4 pages, 3 figures (1 in CMYK color), accepted by Astronomy and Astrophysics, INTEGRAL special issue, 200