3,538 research outputs found
ASCA observations of the galactic bulge hard x-ray source GRS 1758--258
GRS 1758-258 is one of the few persistent hard X-ray emitters (E>100 keV) in
the Galaxy. Using the ASCA satellite, we have obtained the first detailed data
on GRS 1758-258 in the 1-10 keV range, where previous observations were
affected by confusion problems caused by the nearby strong source GX5-1. The
spectrum is well described by a power law with photon index 1.7 without strong
Fe emission lines. A prominent soft excess, as observed with ROSAT when the
hard X-ray flux was in a lower intensity state, was not detected. However, the
presence of a soft spectral component, accounting for at most 5% of the 0.1-300
keV flux, cannot be excluded. The accurate measurement of interstellar
absorption (N_H=(1.5+-0.1) x 10^22 cm -2) corresponds to an optical extinction
which definitely excludes the presence of a massive companion.Comment: 7 pages, AAS latex [11pt,aaspptwo,flushrt,tighten], + 1.ps figure
Accepted for pubblication in ApJ, 09 02 96 Also available at
http://fy.chalmers.se/~haardt/personal/curr.html Figures 1 and 2 available
upon request at [email protected]
Virtual Network Function Embedding with Quantum Annealing
In recent years, the growing number of devices connected to the internet led network operators to continuously expand their own infrastructures. In order to simplify this scaling process, the research community is currently investigating the opportunity to move the complexity from a hardware to a software domain, through the introduction of a new paradigm, called Network Functions Virtualisation (NFV). It considers standard hardware platforms where many virtual instances are allocated to implement specific network services. However, despite the theoretical benefits, the mapping of the different virtual instances to the available physical resources represents a complex problem, difficult to be solved classically. The present work proposes a Quadratic Unconstrained Binary Optimisation (QUBO) formulation of this embedding process, exploring the implementation possibilities on D-Wave's Quantum Annealers. Many test cases, with realistic constraints, have been considered to validate and characterise the potential of the model, and the promising results achieved are discussed throughout the document. The technical discussion is enriched with comparisons of the results obtained through heuristic algorithms, highlighting the strengths and the limitations in the resolution of the QUBO formulation proposed on current quantum machines
3d N = 2 mirror symmetry, pq-webs and monopole superpotentials
D3 branes stretching between webs of (p,q) 5branes provide an interesting
class of 3d N=2 theories. For generic pq-webs however the low energy field
theory is not known. We use 3d mirror symmetry and Type IIB S-duality to
construct Abelian gauge theories corresponding to D3 branes ending on both
sides of a pq-web made of many coincident NS5's intersecting one D5. These
theories contain chiral monopole operators in the superpotential and enjoy a
non trivial pattern of global symmetry enhancements. In the special case of the
pq-web with one D5 and one NS5, the 3d low energy SCFT admits three dual
formulations. This triality can be applied locally inside bigger quiver gauge
theories. We prove our statements using partial mirror symmetry `a la
Kapustin-Strassler, showing the equality of the S^3_b partition functions and
studying the quantum chiral rings
Health related quality of life in COVID-19 survivors discharged from acute hospitals: results of a short-form 36-item survey [version 1; peer review: awaiting peer review]
Background: Health-related quality of life (HRQL) is important for
evaluating the impact of a disease in the longer term across the
physical and psychological domains of human functioning. The aim of
this study is to evaluate HRQL in COVID-19 survivors in Italy using the
short form 36-items questionnaire (SF-36).
Methods: This is an observational study involving adults discharged
home following a coronavirus disease 2019 (COVID-19)-related
hospital admission. Baseline demographic and clinical data including
the Cumulative Illness Rating Scale (CIRS) and the Hospital Anxiety
and Depression Scale (HADS) were collected. The validated Italian
version of SF-36 was administered cross-sectionally. The SF-36
contains eight scales measuring limitations in physical and social
functioning, the impact on roles and activities, fatigue, emotional wellbeing, pain and general health perception.
Results: A total of 35 patients, with a mean age of 60 years,
completed the SF-36. The results showed difficulties across the
physical and psychological domains, particularly affecting the return
to previous roles and activities. A higher burden of co-morbidities as
well as a more severe muscle weakness was associated to a lower
physical functioning. Younger age, rather than older, correlated to a
perceived greater limitation in physical functioning and vitality.
Conclusions: COVID-19 survivors particularly the ones of working age
may need support for resuming their premorbid level of functioning
and returning to work
Small RNA sequencing of cryopreserved semen from single bull revealed altered miRNAs and piRNAs expression between High- and Low-motile sperm populations
Putative piRNA clusters that were assigned by proTRAC to the High Motile (HM) and Low Motile (LM) sperm fractions. (XLSX 21Ă‚Â kb
In silico validation of MCID tool for voxel dosimetry applied to 90Y radioembolization of liver malignancies
The aim of this work is validating the Monte Carlo Internal Dosimetry (MCID) tool for internal dosimetry, which allows personalized treatment planning starting from patient-specific images and direct Monte Carlo (MC) simulations.
The absorbed dose for different computational phantoms, calculated with MC and with conventional MIRD methods at both organ and voxel level, were compared, obtaining differences of about 0.3% and within 3%, respectively, whereas differences increased (up to 14%) introducing tissue heterogeneities in phantoms. The absorbed dose of spheres with different radius (10 mm ≤ r ≤ 30 mm), calculated from MC code and from OLINDA/EXM was also compared, obtaining differences varying in the range 2–9% after correcting for partial volume effects (PVEs) from imaging.
This work validated the MCID tool which allows the fast generation of input macros for MC simulations, starting from patient-specific images. It also shows the impact of tissue inhomogeneities on dosimetric results and their relevance for an accurate dosimetric plan
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