364 research outputs found
BeppoSAX observations of low-energy spectral features in AGN
The combination of the broad band coverage and moderate spectral resolution
of the LECS and MECS instruments on-board BeppoSAX allow the spectra of AGN to
be studied in unprecedented detail down to 0.1 keV. We describe the calibration
and the performance of the LECS and report on observations of low-energy
absorption features in the spectra of both a low (MCG-6-30-15) and a high
luminosity (3C 273) AGN. These features provide important diagnostics on the
location and nature of the material surrounding the AGN. A comparison of LECS
and ASCA/SIS low energy performance is also presented in the case of 3C 273.Comment: 5 pages. To appear in symposium proceedings: The Active X-Ray Sky,
Rome, October 199
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Identifying factors which enhance the self-management of type 2 diabetes: A systematic review with thematic analysis
YesBackground: Individuals with type 2 diabetes play a pivotal role in their health. Enhancing the self-management
of diabetes can improve blood glucose control, and quality of life, and reduce diabetes-related complications. We
have identified factors influencing the self-management of type 2 diabetes to inform strategies that may be applied
in the long-term management of blood glucose control.
Methods: We conducted a systematic literature review of recent studies published between January 2010 to
December 2020 to identify the available evidence on effective self-management strategies for type 2 diabetes. The
databases used for the searchers were Scopus, PubMed, Science Direct, CINAHL, and Google Scholar. We
assessed English language publications only. The screening of titles was duplicated by two researchers. We then
conducted a thematic analysis of the key findings from eligible publications to identify reoccurring messages that
may augment or abate self-management strategies.
Results: We identified 49 relevant publications involving 90,857 participants. Four key themes were identified
from these publications: Individual drive, social capital, Knowledge base, and Insufficient health care. High
motivation and self-efficacy enabled greater self-management. The importance of family, friends, and the health
care professional was salient, as were the negative effects of stigma and labelling. Enablers to good self-management were the level of support provided and its affordability. Finally, the accessibility and adequacy of the
health care services emerged as fundamental to permit diabetes self-management.
Conclusions: Self-management of type 2 diabetes is an essential strategy given its global presence and impact,
and the current resource constraints in health care. Individuals with type 2 diabetes should be empowered and
supported to self-manage. This includes awareness raising on their role in self-health, engaging broader support
networks, and the pivotal role of health care professionals to inform and support. Further research is needed into
the capacity assessment of healthcare systems in diabetes medicine, targeted low-cost resources for self-management, and the financial requirements that enable self-management advice to be enacted.While this research did not receive any specific project funding, KRB is funded by a University of Otago Pacific Ph.D. Scholarship. ANR is funded as a Research Fellow by the National Heart Foundation
Gamma-ray Observations Under Bright Moonlight with VERITAS
Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive
photomultiplier tube (PMT) cameras. Exposure to high levels of background
illumination degrades the efficiency of and potentially destroys these
photo-detectors over time, so IACTs cannot be operated in the same
configuration in the presence of bright moonlight as under dark skies. Since
September 2012, observations have been carried out with the VERITAS IACTs under
bright moonlight (defined as about three times the night-sky-background (NSB)
of a dark extragalactic field, typically occurring when Moon illumination >
35%) in two observing modes, firstly by reducing the voltage applied to the
PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to
the cameras. This has allowed observations at up to about 30 times previous NSB
levels (around 80% Moon illumination), resulting in 30% more observing time
between the two modes over the course of a year. These additional observations
have already allowed for the detection of a flare from the 1ES 1727+502 and for
an observing program targeting a measurement of the cosmic-ray positron
fraction. We provide details of these new observing modes and their performance
relative to the standard VERITAS observations
Full adoption of the most effective strategies to mitigate methane emissions by ruminants can help meet the 1.5 °C target by 2030 but not 2050
To meet the 1.5 °C target, methane (CH) from ruminants must be reduced by 11 to 30% by 2030 and 24 to 47% by 2050 compared to 2010 levels. A meta-analysis identified strategies to decrease product-based (PB; CH per unit meat or milk) and absolute (ABS) enteric CH emissions while maintaining or increasing animal productivity (AP; weight gain or milk yield). Next, the potential of different adoption rates of one PB or one ABS strategy to contribute to the 1.5 °C target was estimated. The database included findings from 430 peer-reviewed studies, which reported 98 mitigation strategies that can be classified into three categories: animal and feed management, diet formulation, and rumen manipulation. A random-effects meta-analysis weighted by inverse variance was carried out. Three PB strategies—namely, increasing feeding level, decreasing grass maturity, and decreasing dietary forage-to-concentrate ratio—decreased CH per unit meat or milk by on average 12% and increased AP by a median of 17%. Five ABS strategies—namely CH inhibitors, tanniferous forages, electron sinks, oils and fats, and oilseeds—decreased daily methane by on average 21%. Globally, only 100% adoption of the most effective PB and ABS strategies can meet the 1.5 °C target by 2030 but not 2050, because mitigation effects are offset by projected increases in CH due to increasing milk and meat demand. Notably, by 2030 and 2050, low- and middle-income countries may not meet their contribution to the 1.5 °C target for this same reason, whereas high-income countries could meet their contributions due to only a minor projected increase in enteric CH emissions.We thank the GLOBAL NETWORK project for generating part of the database. The GLOBAL NETWORK project (https://globalresearchalliance.org/research/livestock/collaborative-activities/global-research-project/; accessed 20 June 2020) was a multinational initiative funded by the Joint Programming Initiative on Food Security, Agriculture, and Climate Change and was coordinated by the Feed and Nutrition Network (https://globalresearchalliance.org/research/livestock/networks/feed-nutrition-network/; accessed 20 June 2020) within the Livestock Research Group of the Global Research Alliance on Agricultural GHG (https://globalresearchalliance.org; accessed 20 June 2020). We thank MitiGate, which was part of the Animal Change project funded by the EU under Grant Agreement FP7-266018 for sharing their database with us (http://mitigate.ibers.aber.ac.uk/, accessed 1 July 2017). Part of C.A., A.N.H., and S.C.M.’s time in the early stages of this project was funded by the Kravis Scientific Research Fund (New York) and a gift from Sue and Steve Mandel to the Environmental Defense Fund. Another part of C.A.’s work on this project was supported by the National Program for Scientific Research and Advanced Studies - PROCIENCIA within the framework of the "Project for the Improvement and Expansion of the Services of the National System of Science, Technology and Technological Innovation" (Contract No. 016-2019) and by the German Federal Ministry for Economic Cooperation and Development (issued through Deutsche Gesellschaft für Internationale Zusammenarbei) through the research “Programme of Climate Smart Livestock” (Programme 2017.0119.2). Part of A.N.H.’s work was funded by the US Department of Agriculture (Washington, DC) National Institute of Food and Agriculture Federal Appropriations under Project PEN 04539 and Accession no. 1000803. E.K. was supported by the Sesnon Endowed Chair Fund of the University of California, Davis
Gravitational Lensing by Black Holes
We review the theoretical aspects of gravitational lensing by black holes,
and discuss the perspectives for realistic observations. We will first treat
lensing by spherically symmetric black holes, in which the formation of
infinite sequences of higher order images emerges in the clearest way. We will
then consider the effects of the spin of the black hole, with the formation of
giant higher order caustics and multiple images. Finally, we will consider the
perspectives for observations of black hole lensing, from the detection of
secondary images of stellar sources and spots on the accretion disk to the
interpretation of iron K-lines and direct imaging of the shadow of the black
hole.Comment: Invited article for the GRG special issue on lensing (P. Jetzer, Y.
Mellier and V. Perlick Eds.). 31 pages, 12 figure
Magnetic Field Amplification in Galaxy Clusters and its Simulation
We review the present theoretical and numerical understanding of magnetic
field amplification in cosmic large-scale structure, on length scales of galaxy
clusters and beyond. Structure formation drives compression and turbulence,
which amplify tiny magnetic seed fields to the microGauss values that are
observed in the intracluster medium. This process is intimately connected to
the properties of turbulence and the microphysics of the intra-cluster medium.
Additional roles are played by merger induced shocks that sweep through the
intra-cluster medium and motions induced by sloshing cool cores. The accurate
simulation of magnetic field amplification in clusters still poses a serious
challenge for simulations of cosmological structure formation. We review the
current literature on cosmological simulations that include magnetic fields and
outline theoretical as well as numerical challenges.Comment: 60 pages, 19 Figure
Full reduction of large finite random Ising systems by RSRG
We describe how to evaluate approximately various physical interesting
quantities in random Ising systems by direct renormalization of a finite
system. The renormalization procedure is used to reduce the number of degrees
of freedom to a number that is small enough, enabling direct summing over the
surviving spins. This procedure can be used to obtain averages of functions of
the surviving spins. We show how to evaluate averages that involve spins that
do not survive the renormalization procedure. We show, for the random field
Ising model, how to obtain the "connected" 2-spin correlation function and the
"disconnected" 2-spin correlation function. Consequently, we show how to obtain
the average susceptibility and the average energy. For an Ising system with
random bonds and random fields we show how to obtain the average specific heat.
We conclude by presenting our numerical results for the average susceptibility
and the "connected" 2-spin correlation function along one of the principal
axes. (We believe this to be the first time, where the full three dimensional
correlation is calculated and not just parameters like Nu or Eta.) The results
for the average susceptibility are used to extract the critical temperature and
critical exponents of the 3D random field Ising system.Comment: 30 pages, 17 figure
Molecular and Historical Aspects of Corn Belt Dent Diversity
Tens-of-thousands of open-pollinated cultivars of corn (Zea mays L.) are being maintained in germplasm banks. Knowledge of the amount and distribution of genetic variation within and among accessions can aid end users in choosing among them. We estimated molecular genetic variation and looked for influences of pedigree, adaptation, and migration in the genetic makeup of conserved Corn-Belt Dent-related germplasm. Plants sampled from 57 accessions representing Corn-Belt Dents, Northern Flints, Southern Dents, plus 12 public inbreds, were genotyped at 20 simple sequence repeat (SSR) loci. For 47 of the accessions, between 5 and 23 plants per accession were genotyped (mean = 9.3). Mean number of alleles per locus was 6.5 overall, 3.17 within accessions, and 3.20 within pooled inbreds. Mean gene diversity was 0.53 within accessions and 0.61 within pooled inbreds. Open-pollinated accessions showed a tendency toward inbreeding (FIS = 0.09), and 85% of genetic variation was shared among them. A Fitch-Margoliash tree strongly supported the distinctiveness of flint from dent germplasm but did not otherwise reveal evidence of genetic structure. Mantel tests revealed significant correlations between genetic distance and geographical (r = 0.54, P= 0.04) or maturity zone (r = 0.33, P = 0.03) distance only if flint germplasm was included in the analyses. A significant correlation (r = 0.76, P \u3c 0.01) was found between days to pollen shed and maturity zone of accession origin. Pedigree, rather than migration or selection, has most influenced the genetic structure of the extant representatives of the open-pollinated cultivars at these SSR loci
Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector
A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino
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