102 research outputs found
Uncovering Offshore Financial Centers: Conduits and Sinks in the Global Corporate Ownership Network
Multinational corporations use highly complex structures of parents and
subsidiaries to organize their operations and ownership. Offshore Financial
Centers (OFCs) facilitate these structures through low taxation and lenient
regulation, but are increasingly under scrutiny, for instance for enabling tax
avoidance. Therefore, the identification of OFC jurisdictions has become a
politicized and contested issue. We introduce a novel data-driven approach for
identifying OFCs based on the global corporate ownership network, in which over
98 million firms (nodes) are connected through 71 million ownership relations.
This granular firm-level network data uniquely allows identifying both
sink-OFCs and conduit-OFCs. Sink-OFCs attract and retain foreign capital while
conduit-OFCs are attractive intermediate destinations in the routing of
international investments and enable the transfer of capital without taxation.
We identify 24 sink-OFCs. In addition, a small set of five countries -- the
Netherlands, the United Kingdom, Ireland, Singapore and Switzerland -- canalize
the majority of corporate offshore investment as conduit-OFCs. Each conduit
jurisdiction is specialized in a geographical area and there is significant
specialization based on industrial sectors. Against the idea of OFCs as exotic
small islands that cannot be regulated, we show that many sink and conduit-OFCs
are highly developed countries
The quiescence optical light curve of Nova Scorpii 1994 (=GRO J1655-40)
We report on extensive V, R, and i band photometry of the black-hole
candidate Nova Sco 1994 (GRO J1655-40) obtained during March 1996, when the
source was close to its quiescent pre-outburst optical brightness (V=17.3).
From our observations and data taken from the literature we derive a refined
ephemeris for inferior conjunction of the secondary star: HJD 2449838.4198(52)
+ 2.62168(14) x N. We have modeled the V, R, and i band light curves in terms
of a Roche lobe filling secondary and an accretion disk around the compact
star, the latter described as a flat cylinder with a radial temperature
distribution. From the shape of the light curve we constrain the binary
inclination and mass of the secondary star to lie in the ranges 63.7-70.7
degrees and 1.60-3.10 Solar masses, respectively. This limits the mass of the
black-hole to the range 6.29-7.60 Solar Masses. The mass range we obtained for
the secondary star is supported by the results of stellar evolution
calculations.Comment: Accepted for publication in Astronomy and Astrophysics Uses L-AA
version 3 8 pages plus 10 ps figure
The anatomy of a population-scale social network
Large-scale human social network structure is typically inferred from digital
trace samples of online social media platforms or mobile communication data.
Instead, here we investigate the social network structure of a complete
population, where people are connected by high-quality links sourced from
administrative registers of family, household, work, school, and next-door
neighbors. We examine this multilayer social opportunity structure through
three common concepts in network analysis: degree, closure, and distance.
Findings present how particular network layers contribute to presumably
universal scale-free and small-world properties of networks. Furthermore, we
suggest a novel measure of excess closure and apply this in a life-course
perspective to show how the social opportunity structure of individuals varies
along age, socio-economic status, and education level. Our work provides new
entry points to understand individual socio-economic failure and success as
well as persistent societal problems of inequality and segregation
The dynamics of eccentric accretion discs in superhump systems
We have applied an eccentric accretion disc theory in simplified form to the
case of an accretion disc in a binary system, where the disc contains the 3:1
Lindblad resonance. This is relevant to the case of superhumps in SU Ursae
Majoris cataclysmic variables and other systems, where it is thought that this
resonance leads to growth of eccentricity and a modulation in the light curve
due to the interaction of a precessing eccentric disc with tidal stresses. A
single differential equation is formulated which describes the propagation,
resonant excitation and viscous damping of eccentricity. The theory is first
worked out in the simple case of a narrow ring and leads to the conclusion that
the eccentricity distribution is locally suppressed by the presence of the
resonance, creating a dip in the eccentricity at the resonant radius.
Application of this theory to the superhump case confirms this conclusion and
produces a more accurate expression for the precession rate of the disc than
has been previously accomplished with simple dynamical estimates.Comment: 10 pages, 11 figures. Accepted for publication in MNRA
Suzaku X-ray Spectra and Pulse Profile Variations during the Superorbital Cycle of LMC X-4
We present results from spectral and temporal analyses of Suzaku and RXTE
observations of the high mass X-ray binary LMC X-4. Using the full 13 years of
available RXTE/ASM data, we apply the ANOVA and Lomb normalized Periodogram
methods to obtain an improved superorbital period measurement of 30.32 +/- 0.04
days. The phase-averaged X-ray spectra from Suzaku observations during the high
state of the superorbital period can be modeled in the 0.6--50 keV band as the
combination of a power-law with Gamma ~ 0.6 and a high-energy cutoff at ~ 25
keV, a blackbody with kT_BB ~ 0.18 keV, and emission lines from Fe K_alpha, O
VIII, and Ne IX (X Lyalpha). Assuming a distance of 50 kpc, The source has
luminosity L_X ~ 3 x 10^38 ergs s^-1 in the 2--50 keV band, and the luminosity
of the soft (blackbody) component is L_BB ~ 1.5 x 10^37 ergs s^-1. The energy
resolved pulse profiles show single-peaked soft (0.5-1 keV) and hard (6-10 keV)
pulses but a more complex pattern of medium (2-10 keV) pulses;
cross-correlation of the hard with the soft pulses shows a phase shift that
varies between observations. We interpret these results in terms of a picture
in which a precessing disk reprocesses the hard X-rays and produces the
observed soft spectral component, as has been suggested for the similar sources
Her X-1 and SMC X-1.Comment: 13 emulateapj pages, 11 figures, 4 tables; accepted for publication
in Ap
Stability of general-relativistic accretion disks
Self-gravitating relativistic disks around black holes can form as transient
structures in a number of astrophysical scenarios such as binary neutron star
and black hole-neutron star coalescences, as well as the core-collapse of
massive stars. We explore the stability of such disks against runaway and
non-axisymmetric instabilities using three-dimensional hydrodynamics
simulations in full general relativity using the THOR code. We model the disk
matter using the ideal fluid approximation with a -law equation of
state with . We explore three disk models around non-rotating black
holes with disk-to-black hole mass ratios of 0.24, 0.17 and 0.11. Due to metric
blending in our initial data, all of our initial models contain an initial
axisymmetric perturbation which induces radial disk oscillations. Despite these
oscillations, our models do not develop the runaway instability during the
first several orbital periods. Instead, all of the models develop unstable
non-axisymmetric modes on a dynamical timescale. We observe two distinct types
of instabilities: the Papaloizou-Pringle and the so-called intermediate type
instabilities. The development of the non-axisymmetric mode with azimuthal
number m = 1 is accompanied by an outspiraling motion of the black hole, which
significantly amplifies the growth rate of the m = 1 mode in some cases.
Overall, our simulations show that the properties of the unstable
non-axisymmetric modes in our disk models are qualitatively similar to those in
Newtonian theory.Comment: 30 pages, 21 figure
Study Protocol for the Development of a European eHealth Platform to Improve Quality of Life in Individuals With Huntington's Disease and Their Partners (HD-eHelp Study): A User-Centered Design Approach
Background: Huntington's disease (HD) is an autosomal dominant neurodegenerative disease that affects the quality of life (QoL) of HD gene expansion carriers (HDGECs) and their partners. Although HD expertise centers have been emerging across Europe, there are still some important barriers to care provision for those affected by this rare disease, including transportation costs, geographic distance of centers, and availability/accessibility of these services in general. eHealth seems promising in overcoming these barriers, yet research on eHealth in HD is limited and fails to use telehealth services specifically designed to fit the perspectives and expectations of HDGECs and their families. In the European HD-eHelp study, we aim to capture the needs and wishes of HDGECs, partners of HDGECs, and health care providers (HCPs) in order to develop a multinational eHealth platform targeting QoL of both HDGECs and partners at home.Methods: We will employ a participatory user-centered design (UCD) approach, which focusses on an in-depth understanding of the end-users' needs and their contexts. Premanifest and manifest adult HDGECs (n = 76), partners of HDGECs (n = 76), and HCPs (n = 76) will be involved as end-users in all three phases of the research and design process: (1) Exploration and mapping of the end-users' needs, experiences and wishes; (2) Development of concepts in collaboration with end-users to ensure desirability; (3) Detailing of final prototype with quick review rounds by end-users to create a positive user-experience. This study will be conducted in the Netherlands, Germany, Czech Republic, Italy, and Ireland to develop and test a multilingual platform that is suitable in different healthcare systems and cultural contexts.Discussion: Following the principles of UCD, an innovative European eHealth platform will be developed that addresses the needs and wishes of HDGECs, partners and HCPs. This allows for high-quality, tailored care to be moved partially into the participants' home, thereby circumventing some barriers in current HD care provision. By actively involving end-users in all design decisions, the platform will be tailored to the end-users' unique requirements, which can be considered pivotal in eHealth services for a disease as complex and rare as HD
Short-term beneficial effects of methylene blue on kidney damage in septic shock patients
Contains fulltext :
71022.pdf (publisher's version ) (Closed access)OBJECTIVE: We previously demonstrated that upregulation of renal inducible nitric oxide synthase (iNOS) is associated with proximal tubule injury during systemic inflammation in humans. In this study we investigated the short-term effect of methylene blue (MB), an inhibitor of the NO pathway, on kidney damage and function in septic shock patients. DESIGN AND SETTING: A prospective clinical study conducted in an intensive care unit. PATIENTS: Nine patients (four men, five women, mean age 71 +/- 3 years) with confirmed or suspected bacterial infection and with refractory septic shock defined as a mean arterial pressure or = 0.2 microg/kg per minute. INTERVENTIONS: A 4 h continuous intravenous infusion of 1 mg/kg MB per hour. MEASUREMENTS AND RESULTS: The urinary excretion of NO metabolites decreased with median 90% (range 75-95%) from baseline to 6 h after MB administration. The first 24 h creatinine clearance improved by 51% (18-173%) after MB treatment but was still strongly impaired. During the first 6 h after the start of MB treatment both the urinary excretion of cytosolic glutathione S-transferase A1-1 and P1-1, markers for proximal and distal tubule damage, respectively, decreased by 45% (10-70%) and 70% (40-85) vs. baseline. After termination of the MB infusion the NO metabolites and markers of tubular injury returned to pretreatment levels. CONCLUSIONS: In septic patients with refractory shock short-term infusion of MB is associated with a decrease in NO production and an attenuation of the urinary excretion of renal tubular injury markers
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