873 research outputs found
Proper Motions of H-alpha filaments in the Supernova Remnant RCW 86
We present a proper motion study of the eastern shock-region of the supernova
remnant RCW 86 (MSH 14-63, G315.4-2.3), based on optical observations carried
out with VLT/FORS2 in 2007 and 2010. For both the northeastern and southeastern
regions, we measure an average proper motion of H-alpha filaments of 0.10 +/-
0.02 arcsec/yr, corresponding to 1200 +/- 200 km/s at 2.5kpc. There is
substantial variation in the derived proper motions, indicating shock
velocities ranging from just below 700 km/s to above 2200 km/s.
The optical proper motion is lower than the previously measured X-ray proper
motion of northeastern region. The new measurements are consistent with the
previously measured proton temperature of 2.3 +/- 0.3 keV, assuming no
cosmic-ray acceleration. However, within the uncertainties, moderately
efficient (< 27 per cent) shock acceleration is still possible. The combination
of optical proper motion and proton temperature rule out the possibility that
RCW 86 has a distance less than 1.5kpc.
The similarity of the proper motions in the northeast and southeast is
peculiar, given the different densities and X-ray emission properties of the
regions. The northeastern region has lower densities and the X-ray emission is
synchrotron dominated, suggesting that the shock velocities should be higher
than in the southeastern, thermal X-ray dominated, region. A possible solution
is that the H-alpha emitting filaments are biased toward denser regions, with
lower shock velocities. Alternatively, in the northeast the shock velocity may
have decreased rapidly during the past 200yr, and the X-ray synchrotron
emission is an afterglow from a period when the shock velocity was higher.Comment: Accepted for publication in MNRA
The perceived influence of Christian leadership competencies during COVID-19
Purpose: Surviving the coronavirus disease 2019 (COVID-19) pandemic required much of leaders. It highlighted the complexities of faith in the workplace. Christian business leaders drew on their faith to influence employees’ work intentions and behaviours through specific leadership competencies. This study aimed to gain insights into the leadership competencies of Christian leaders during COVID-19 and its perceived influence on colleagues’ values and workplace behaviour through the leaders’ integration of faith and work.
Design/methodology/approach:Â The study used a qualitative, grounded theory approach with semi-structured interviews to collect data. Participants (NÂ = 14) were full-time Christian leaders selected through purposeful, convenient, and snowball sampling.
Findings/results:Â The findings indicated that Christian business leaders exhibited distinctive leadership competencies attributed to their faith. These competencies allowed them to express their beliefs to co-workers in ways that surpassed verbal communication.
Practical implications:Â Organisations should consider implementing leadership development programmes focusing on integrating faith and values into leadership practices. Providing Christian leaders with tools and resources to align their leadership approach with their spiritual beliefs can enhance their ability to create a positive and ethical workplace culture.
Contribution/value-add: Although no study has directly explored religion’s role in dealing with pandemics, understanding the impact of beliefs such as Christian religiosity on work can complement management and organisational practices. The findings contribute to leadership studies by laying the groundwork for future investigation into the role of faith integration in leadership behaviours and outcomes
HPV type concordance in sexual couples determines the effect of condoms on regression of flat penile lesions
We earlier demonstrated, in a randomised clinical trial, that the regression time of flat penile lsions in male sexual partners of women with cervical intraepithelial neoplasia (CIN) was shorter in men who used condoms compared to those who did not. To further evaluate this finding, we examined whether the effect of condom use on the regression of flat penile lesions depends on the presence of human papillomavirus (HPV) type concordance in sexual couples, as determined in cervical and penile scrapes by GP5+/6+ PCR testing. A Cox model with time-dependent covariates showed a beneficial effect of condoms on regression of flat penile lesions in concordant couples (hazard ratio 2.63, 95% CI 1.07–6.48) but not in those who were nonconcordant. When both partners harboured different HPV types, no effect of condoms was found (hazard ratio 0.90, 95% CI 0.27–2.96). Delayed regression of flat penile lesions was associated with either stable lesions or with new penile lesions developing at sites surrounding pre-existing lesions suggesting reinfection of the penile epithelium. We conclude that condom use blocks sexual HPV transmission by preventing reinfection and development of new penile lesions in men who are susceptible to the same type as present in the female partner
Female home range size is regulated by resource distribution and intraspecific competition: a long-term field study
The size of an individual’s home range is an important feature, influencing reproduction and survival, but it can vary considerably among both populations and individuals. The factors accounting for such variation are still poorly understood, and comprehensive long-term field studies considering various environmental factors that influence home range size are rare. We investigated the effects of seasonality, availability of food, cover, number of direct neighbours and the relative individual body mass on home range sizes in 125 adult female striped mice, Rhabdomys pumilio, in South Africa from 2004 to 2008. We used radiotelemetry to estimate home range sizes, trapping to determine the number of direct neighbours, and plant surveys in every home range to determine availability of food and cover. Home ranges were smaller when food quantity was high, many territorial neighbours were present, females had a relatively small body mass and during the nonbreeding season. We conclude
that the availability of food resources and intraspecific competition are the main factors influencing home range size in female striped mice. Females enlarged their home ranges when territorial neighbours were few, and there was a significant positive correlation between home range size and quantity of food plants. This indicates that home range size might not reflect the minimal trade-off between access to resources that allow for a female’s survival and lowest cost for defending and foraging in that area. Instead, we propose a hypothesis for future research that female striped mice occupy areas several times larger than needed to improve their fitness by providing resources for future offspring
Correction:Intraoperative fluoroscopic protocol to avoid rotational malalignment after nailing of tibia shaft fractures: introduction of the ‘C-Arm Rotational View (CARV)’ (European Journal of Trauma and Emergency Surgery, (2022), 10.1007/s00068-022-02038-2)
In the Acknowledgements section the following part was missing: On behalf of the Traumaplatform 3D Consortium: L. M. Goedhart, B. de Cort, L. A. M. Hendrickx, M. ter Horst, J. Gorter, R. J. van Luit, P. Nieboer, W. Füssenich, T. Zwerver, R. Koster, J. J. Valk, L. Reinke, J. G. Bleeker, M. Cain, F. J. P. Beeres, G. M. M. J. Kerkhoffs. The original article has been corrected
The Radial Structure of the Cygnus Loop Supernova Remnant --- Possible evidence of a cavity explosion ---
We observed the North-East (NE) Limb toward the center region of the Cygnus
Loop with the ASCA Observatory. We found a radial variation of electron
temperature (kTe) and ionization timescale (log(\tau)) whereas no variation
could be found for the abundances of heavy elements. In this paper, we
re-analyzed the same data set and new observations with the latest calibration
files. Then we constructed the precise spatial variations of kTe, log(\tau),
and abundances of O, Ne, Mg, Si, and Fe over the field of view (FOV). We found
a spatial variation not only in kTe and in log(\tau) but also in most of heavy
elements. As described in Miyata et al. (1994), values of kTe increase and
those of log(\tau) decrease toward the inner region. We found that the
abundance of heavy elements increases toward the inner region. The radial
profiles of O, Ne, and Fe show clear jump structures at a radius of 0.9 Rs,
where Rs is the shock radius. Outside of 0.9 Rs, abundances of all elements are
constant. On the contrary, inside of 0.9 Rs, abundances of these elements are
20--30 % larger than those obtained outside of 0.9 Rs. The radial profile of
kTe also shows the jump structure at 0.9 Rs. This means that the hot and metal
rich plasma fills the volume inside of 0.9 Rs. We concluded that this jump
structure was the possible evidence for the pre-existing cavity produced by the
precursor. If the ejecta fills inside of 0.9 Rs, the total mass of the ejecta
was roughly 4\Msun. We then estimated the main-sequence mass to be roughly
15\Msun, which supports the massive star in origin of the Cygnus Loop supernova
remnant and the existence of a pre-existing cavity.Comment: 37 pages, 14 figures. Accepted for publication of Ap
Signs and symptoms in children with a serious infection: a qualitative study
BACKGROUND: Early diagnosis of serious infections in children is difficult in general practice, as incidence is low, patients present themselves at an early stage of the disease and diagnostic tools are limited to signs and symptoms from observation, clinical history and physical examination. Little is known which signs and symptoms are important in general practice. With this qualitative study, we aimed to identify possible new important diagnostic variables. METHODS: Semi-structured interviews with parents and physicians of children with a serious infection. We investigated all signs and symptoms that were related to or preceded the diagnosis. The analysis was done according to the grounded theory approach. Participants were recruited in general practice and at the hospital. RESULTS: 18 children who were hospitalised because of a serious infection were included. On average, parents and paediatricians were interviewed 3 days after admittance of the child to hospital, general practitioners between 5 and 8 days after the initial contact. The most prominent diagnostic signs in seriously ill children were changed behaviour, crying characteristics and the parents' opinion. Children either behaved drowsy or irritable and cried differently, either moaning or an inconsolable, loud crying. The parents found this illness different from previous illnesses, because of the seriousness or duration of the symptoms, or the occurrence of a critical incident. Classical signs, like high fever, petechiae or abnormalities at auscultation were helpful for the diagnosis when they were present, but not helpful when they were absent. CONCLUSION: behavioural signs and symptoms were very prominent in children with a serious infection. They will be further assessed for diagnostic accuracy in a subsequent, quantitative diagnostic study
XMM-Newton Spectroscopy of the Cluster of Galaxies 2A 0335+096
We present here the results of a deep (130 ks) XMM-Newton observation of the
cluster of galaxies 2A 0335+096. The deep exposure allows us to study in detail
its temperature structure and its elemental abundances. We fit three different
thermal models and find that the multi-temperature wdem model fits our data
best. We find that the abundance structure of the cluster is consistent with a
scenario where the relative number of Type Ia supernovae contributing to the
enrichment of the intra-cluster medium is ~25%, while the relative number of
core collapse supernovae is ~75%. Comparison of the observed abundances to the
supernova yields does not allow us to put any constrains on the contribution of
Pop III stars to the enrichment of the ICM. Radial abundance profiles show a
strong central peak of both Type Ia and core collapse supernova products. Both
the temperature and iron abundance maps show an asymmetry in the direction of
the elongated morphology of the surface brightness. In particular the
temperature map shows a sharp change over a brightness edge on the southern
side of the core, which was identified as a cold front in the Chandra data.
This suggests that the cluster is in the process of a merger with a subcluster.
Moreover, we find that the blobs or filaments discovered in the core of the
cluster by Chandra are, contrary to the previous results, colder than the
ambient gas and they appear to be in pressure equilibrium with their
environment.Comment: Accepted for publication in A&A, 19 page
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