1,518 research outputs found
Alien Registration- Cowie, James Thomas V. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/24087/thumbnail.jp
Two-component model of the interaction of an interstellar cloud with surrounding hot plasma
We present a two-component gasdynamic model of an interstellar cloud embedded
in a hot plasma. It is assumed that the cloud consists of atomic hydrogen gas,
interstellar plasma is quasineutral. Hydrogen atoms and plasma protons interact
through a charge exchange process. Magnetic felds and radiative processes are
ignored in the model. The influence of heat conduction within plasma on the
interaction between a cloud and plasma is studied. We consider the extreme case
and assume that hot plasma electrons instantly heat the plasma in the
interaction region and that plasma flow can be described as isothermal. Using
the two-component model of the interaction of cold neutral cloud and hot
plasma, we estimate the lifetime of interstellar clouds. We focus on the clouds
typical for the cluster of local interstellar clouds embedded in the hot Local
Bubble and give an estimate of the lifetime of the Local interstellar cloud
where the Sun currently travels. The charge transfer between highly charged
plasma ions and neutral atoms generates X-ray emission. We assume typical
abundance of heavy ions for the Local Bubble plasma and estimate the X-ray
emissivity due to charge exchange from the interface between cold neutral cloud
and hot plasma. Our results show that charge exchange X-ray emission from the
neutral-plasma interfaces can be a non-negligible fraction of the observed
X-ray emission.Comment: 9 pages, 7 figure
Gravitational lensing due to dark matter modelled by vector field
The specified constant 4-vector field reproducing the spherically symmetric
stationary metric of cold dark matter halo in the region of flat rotation
curves results in a constant angle of light deflection at small impact
distances. The effective deflecting mass is factor greater than the
dark matter mass. The perturbation of deflection picture due to the halo edge
is evaluated.Comment: 17 pages, LaTeX iopart class, 10 eps figures; explanaitions and
discussion are extended and improved, reference added; version to appear in
Classical and Quantum Gravit
A low escape fraction of ionizing photons of L>L* Lyman break galaxies at z=3.3
We present an upper limit for the relative escape fraction (f_{esc}^{rel}) of
ionizing radiation at z~3.3 using a sample of 11 Lyman Break Galaxies (LBGs)
with deep imaging in the U band obtained with the Large Binocular Camera,
mounted on the prime focus of the Large Binocular Telescope. We selected 11
LBGs with secure redshift in the range 3.27<z<3.35, from 3 independent fields.
We stacked the images of our sources in the R and U band, which correspond to
an effective rest-frame wavelength of 1500\AA and 900\AA respectively,
obtaining a limit in the U band image of >=30.7(AB)mag at 1 sigma. We derive a
1 sigma upper limit of f_{esc}^{rel}~5%, which is one of the lowest values
found in the literature so far at z~3.3. Assuming that the upper limit for the
escape fraction that we derived from our sample holds for all galaxies at this
redshift, the hydrogen ionization rate that we obtain (Gamma_{-12}<0.3 s^{-1})
is not enough to keep the IGM ionized and a substantial contribution to the UV
background by faint AGNs is required. Since our sample is clearly still limited
in size, larger z~3 LBG samples, at similar or even greater depths are
necessary to confirm these results on a more firm statistical basis.Comment: 15 pages, 2 figures, 1 table, accepted for publication in Ap
Space-Time Variation of Physical Constants and Relativistic Corrections in Atoms
Detection of high-redshift absorption in the optical spectra of quasars have
provided a powerful tool to measure spatial and temporal variations of physical
``constants'' in the Universe. It is demonstrated that high sensitivity to the
variation of the fine structure constant alpha can be obtained from a
comparison of the spectra of heavy and light atoms (or molecules). We have
performed calculations for the pair FeII and MgII for which accurate quasar and
laboratory spectra are available. A possibility of times enhanced
effects of the fundamental constants variation suitable for laboratory
measurements is also discussed.Comment: 8 pages; LaTeX; Submitted to Phys. Rev. Let
Understanding the training and education needs of homecare workers supporting people with dementia and cancer: a systematic review of reviews
Many people with dementia, supported by family carers, prefer to live at home and may rely on homecare support services. People with dementia are also often living with multimorbidities, including cancer. The main risk factor for both cancer and dementia is age and the number of people living with dementia and cancer likely to rise. Upskilling the social care workforce to facilitate more complex care is central to national workforce strategies and challenges. Training and education development must also respond to the key requirements of a homecare workforce experiencing financial, recruitment and retention difficulties. This systematic review of reviews provides an overview of dementia and cancer training and education accessible to the homecare workforce. Findings reveal there is a diverse range of training and education available, with mixed evidence of effectiveness. Key barriers and facilitators to effective training and education are identified in order to inform future training, education and learning development for the homecare workforce supporting people with dementia and cancer
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Bullying at University: The Social and Legal Contexts of Cyberbullying Among University Students
Students within the university sector are ‘digital natives’. Technology is not ‘new’ or ‘alien’ to them, but rather it is an accepted and normalised part of everyday life (Simmons et al., 2016). With this level of expertise and competence, we could assume that university students are relatively happy with their online relationships. However, in recent years there has been a growing realisation that, for some students at least, the online world is a very dangerous place.The age of the students is of key importance here too, as those in higher and further education are young adults, rather than children in need of parental support. From this perspective, the university as an institution has a duty of care to its students in their learning environment regardless of their age. In this article, we consider the social and cultural contexts which either promote or discourage cyberbullying among university students. Finally, the implications for policies, training and awareness-raising are discussed along with ideas for possible future research in this under researched area
The Calar Alto Deep Imaging Survey: K-band Galaxy Number Counts
We present K-band number counts for the faint galaxies in the Calar Alto Deep
Imaging Survey (CADIS). We covered 4 CADIS fields, a total area of 0.2deg^2, in
the broad band filters B, R and K. We detect about 4000 galaxies in the K-band
images, with a completeness limit of K=19.75mag, and derive the K-band galaxy
number counts in the range of 14.25 < K < 19.75mag. This is the largest medium
deep K-band survey to date in this magnitude range. The B- and R-band number
counts are also derived, down to completeness limits of B=24.75mag and
R=23.25mag. The K-selected galaxies in this magnitude range are of particular
interest, since some medium deep near-infrared surveys have identified breaks
of both the slope of the K-band number counts and the mean B-K color at
K=17\sim18mag. There is, however, a significant disagreement in the K-band
number counts among the existing surveys. Our large near-infrared selected
galaxy sample allows us to establish the presence of a clear break in the slope
at K=17.0mag from dlogN/dm = 0.64 at brighter magnitudes to dlogN/dm = 0.36 at
the fainter end. We construct no-evolution and passive evolution models, and
find that the passive evolution model can simultaneously fit the B-, R- and
K-band number counts well. The B-K colors show a clear trend to bluer colors
for K > 18mag. We also find that most of the K=18-20mag galaxies have a B-K
color bluer than the prediction of a no-evolution model for an L_* Sbc galaxy,
implying either significant evolution, even for massive galaxies, or the
existence of an extra population of small galaxies.Comment: Accepted for A&A, 10 pages, 7 figure
A Baseline Numeric Analysis of Network Telescope Data for Network Incident Discovery
This paper investigates the value of Network Telescope data as a mechanism for network incident discovery by considering data summa-rization, simple heuristic identification and deviations from previously observed traffic distributions. It is important to note that the traffic ob-served is obtained from a Network Telescope and thus does not expe-rience the same fluctuations or vagaries experienced by normal traffic. The datasets used for this analysis were obtained from a Network Tele-scope for the time period August 2005 to September 2009 which had been allocated a Class-C network address block at Rhodes University. The nature of the datasets were considered in terms of simple statistical measures obtained through data summarization which greatly reduced the processing and observation required to determine whether an inci-dent had occurred. However, this raised issues relating to the time in-terval used for identification of an incident. A brief discussion into statis-tical summaries of Network Telescope data as" good" security metrics is provided. The summaries derived were then used to seek for signs of anomalous network activity. Anomalous activity detected was then rec-onciled by considering incidents that had occurred in the same or simi-lar time interval. Incidents identified included Conficker, Win32. RinBot, DDoS and Norton Netware vulnerabilities. Detection techniques includ-ed identification of rapid growth in packet count, packet size deviations, changes in the composition of the traffic expressed as a ratio of its constituents and changes in the modality of the data. Discussion into the appropriateness of this sort of manual analysis is provided and suggestions towards an automated solution are discussed
Hospitalisation and mortality in patients with comorbid COPD and heart failure: a systematic review and meta-analysis
Background Discrepancy exists amongst studies investigating the effect of comorbid heart failure (HF) on the morbidity and mortality of chronic obstructive pulmonary disease (COPD) patients. Methods MEDLINE and Embase were searched using a pre-specified search strategy for studies comparing hospitalisation, rehospitalisation, and mortality of COPD patients with and without HF. Studies must have reported crude and/or adjusted rate ratios, risk ratios, odds ratios (OR), or hazard ratios (HR). Results Twenty-eight publications, reporting 55 effect estimates, were identified that compared COPD patients with HF with those without HF. One study reported on all-cause hospitalisation (1 rate ratio). Two studies reported on COPD-related hospitalisation (1 rate ratio, 2 OR). One study reported on COPD- or cardiovascular-related hospitalisation (4 HR). One study reported on 90-day all-cause rehospitalisation (1 risk ratio). One study reported on 3-year all-cause rehospitalisation (2 HR). Four studies reported on 30-day COPD-related rehospitalisation (1 risk ratio; 5 OR). Two studies reported on 1-year COPD-related rehospitalisation (1 risk ratio; 1 HR). One study reported on 3-year COPD-related rehospitalisation (2 HR). Eighteen studies reported on all-cause mortality (1 risk ratio; 4 OR; 24 HR). Five studies reported on all-cause inpatient mortality (1 risk ratio; 4 OR). Meta-analyses of hospitalisation and rehospitalisation were not possible due to insufficient data for all individual effect measures. Meta-analysis of studies requiring spirometry for the diagnosis of COPD found that risk of all-cause mortality was 1.61 (pooled HR; 95%CI: 1.38, 1.83) higher in patients with HF than in those without HF. Conclusions In this systematic review, we investigated the effect of HF comorbidity on hospitalisation and mortality of COPD patients. There is substantial evidence that HF comorbidity increases COPD-related rehospitalisation and all-cause mortality of COPD patients. The effect of HF comorbidity may differ depending on COPD phenotype, HF type, or HF severity and should be the topic of future research
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