402 research outputs found
The Chandra X-Ray Observatory's Radiation Environment and the AP-8/AE-8 Model
The Chandra X-ray Observatory (CXO) was launched on July 23, 1999 and reached
its final orbit on August 7, 1999. The CXO is in a highly elliptical orbit,
approximately 140,000 km x 10,000 km, and has a period of approximately 63.5
hours (~ 2.65 days). It transits the Earth's Van Allen belts once per orbit
during which no science observations can be performed due to the high radiation
environment. The Chandra X-ray Observatory Center (CXC) currently uses the
National Space Science Data Center's ``near Earth'' AP-8/AE-8 radiation belt
model to predict the start and end times of passage through the radiation
belts. However, our scheduling software uses only a simple dipole model of the
Earth's magnetic field. The resulting B, L magnetic coordinates, do not always
give sufficiently accurate predictions of the start and end times of transit of
the Van Allen belts. We show this by comparing to the data from Chandra's
on-board radiation monitor, the EPHIN (Electron, Proton, Helium Instrument
particle detector) instrument. We present evidence that demonstrates this
mis-timing of the outer electron radiation belt as well as data that also
demonstrate the significant variablity of one radiation belt transit to the
next as experienced by the CXO. We also present an explanation for why the
dipole implementation of the AP-8/AE-8 model is not ideally suited for the CXO.
Lastly, we provide a brief discussion of our on-going efforts to identify a
model that accounts for radiation belt variability, geometry, and one that can
be used for observation scheduling purposes.Comment: 12 pgs, 6 figs, for SPIE 4012 (Paper 76
The Hard X-Ray View of Reflection, Absorption, and the Disk-Jet Connection in the Radio-Loud AGN 3C 33
We present results from Suzaku and Swift observations of the nearby radio
galaxy 3C 33, and investigate the nature of absorption, reflection, and jet
production in this source. We model the 0.5-100 keV nuclear continuum with a
power law that is transmitted either through one or more layers of pc-scale
neutral material, or through a modestly ionized pc-scale obscurer. The standard
signatures of reflection from a neutral accretion disk are absent in 3C 33:
there is no evidence of a relativistically blurred Fe K emission line,
and no Compton reflection hump above 10 keV. We find the upper limit to the
neutral reflection fraction is R<0.41 for an e-folding energy of 1 GeV. We
observe a narrow, neutral Fe K line, which is likely to originate at
least 2,000 R_s from the black hole. We show that the weakness of reflection
features in 3C 33 is consistent with two interpretations: either the inner
accretion flow is highly ionized, or the black-hole spin configuration is
retrograde with respect to the accreting material.Comment: 12 pages, 11 figures, 4 tables. Accepted for publication in Ap
London Creative and Digital Fusion
date-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +0000date-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +0000The London Creative and Digital Fusion programme of interactive, tailored and in-depth support was designed to support the UK capital’s creative and digital companies to collaborate, innovate and grow. London is a globally recognised hub for technology, design and creative genius. While many cities around the world can claim to be hubs for technology entrepreneurship, London’s distinctive potential lies in the successful fusion of world-leading technology with world-leading design and creativity. As innovation thrives at the edge, where better to innovate than across the boundaries of these two clusters and cultures? This booklet tells the story of Fusion’s innovation journey, its partners and its unique business support. Most importantly of all it tells stories of companies that, having worked with London Fusion, have innovated and grown. We hope that it will inspire others to follow and build on our beginnings.European Regional Development Fund 2007-13
Efficacy and Safety of Varenicline for Smoking Cessation in Schizophrenia: A Meta-Analysis
Objective: Smoking represents a major public health problem among patients with schizophrenia. To this end, some studies have investigated the efficacy of varenicline for facilitating smoking cessation in schizophrenia patients. The present review seeks to synthesize the results of these studies as well as document the reported side effects of using this medication.
Methods: An electronic search was performed using five major databases: PubMed, Scopus, EMBASE, Web of Science, and Cochrane Library. Included in the current analysis were randomized clinical trials (RCTs) that have investigated the effect of varenicline in promoting smoking cessation in patients with schizophrenia. Risk of bias among included RCTs was assessed using the Cochrane Collaboration’s quality assessment tool.
Results: Among the 828 screened articles, only four RCTs, which involved 239 participants, were eligible for meta-analysis. In patients with schizophrenia, varenicline treatment when compared to placebo significantly reduced the number of cigarettes consumed per day [SMD (95% CI) = 0.89(0.57–1.22)] and expired carbon monoxide levels [SMD (95% CI) = 0.50 (0.06–0.94)] respectively.
Conclusion: Despite a limited number of studies included in the meta-analysis, our results suggest that varenicline is an effective and safe drug to assist smoking cessation in patients with schizophrenia. Future large-scale well-designed RCTs are required to validate these findings
Black hole growth and host galaxy morphology
We use data from large surveys of the local Universe (SDSS+Galaxy Zoo) to
show that the galaxy-black hole connection is linked to host morphology at a
fundamental level. The fraction of early-type galaxies with actively growing
black holes, and therefore the AGN duty cycle, declines significantly with
increasing black hole mass. Late-type galaxies exhibit the opposite trend: the
fraction of actively growing black holes increases with black hole mass.Comment: 4 pages, 2 figures. Proceedings of the IAU Symposium no. 267,
"Co-Evolution of Central Black Holes and Galaxies: Feeding and Feedback",
eds. B.M. Peterson, R.S. Somerville and T. Storchi-Bergman
RELATIONSHIP OF ENVIROMENTAL SANITATION AND HISTORY OF INFECTIOUS DISEASES WITH THE INCIDENCE OF STUNTING TO CHILDREN WITH AGED 6-23 MONTHS IN THE WORKING AREA OF PATIMPENG HEALTH CARE BONE DISTRICT
Pendahuluan: Baduta yang stunting merupakan hasil dari masalah gizi kronik sebagai akibat dari asupan makanan yang kurang, ditambah dengan penyakit infeksi, dan masalahlingkungan. Baduta stunting dalam jangka pendek dapat mengalami perkembangan yangterhambat, penurunan fungsi kognitif, penurunan fungsi kekebalan tubuh hingga gangguansistem pembakaran dan pada jangka panjang yaitu pada masa dewasa dapat menimbulkanrisiko penyakit degeneratif. Tujuan : Penelitian ini bertujuan untuk mengetahui hubunganantara sanitasi lingkungan dan riwayat penyakit infeksi dengan kejadian stunting pada anakbaduta. Bahan dan Metode : Jenis penelitian ini adalah penelitian desain cross sectional.Sampel yang diambil adalah semua bayi 6-23 bulan yang berada di wilayah kerja PuskesmasPatimpeng Kab. Bone yang berjumlah 125 orang dengan teknik pengambilan sampelpurposive sampling. Analisis data dilakukan dengan analisis univariat dan bivariat. Hasil :Hasil penelitian menunjukkan terdapat 25,6% anak yang menderita stunting. Berdasarkanhasil uji statistik menggunakan chi square dan fisher’s, pada variabel sanitasi lingkunganmenunjukkan tidak terdapat hubungan antara sarana air bersih, sarana pembuangan tinja,tempat pembuangan sampah dan saluran pembuangan air limbah dengan kejadian stuntingpada anak usia 6-23 bulan dengan masing-masing nilai p (0,270), (0,161), (1,000) dan(0,148). Sedangkan pada variabel riwayat penyakit infeksi juga menunjukkan tidak terdapathubungan antara riwayat diare dan riwayat infeksi saluran pernapasan (ISPA) dengankejadian stunting pada anak usia 6-23 bulan dengan masing-masing nilai p (0,679) dan(0,839)
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