75 research outputs found
Kapitalverflechtungen in Deutschland: 1996 - 2010
In den Netzwerkgrafiken, werden die 100 gröĂten Unternehmen erfasst, die ĂŒber Kapitalverflechtungen mit anderen Unternehmen verbunden waren. So entstanden im Zeitraum von 1996 bis 2010 Momentaufnahmen des deutschen Unternehmensnetzwerks â jeweils in AbstĂ€nden von zwei Jahren. Mit jedem Zwei-Jahres-Schritt zeigt sich: Die Kerne des Netzwerks werden kleiner, sie sind lockerer verknĂŒpft und mit weniger Unternehmen auĂerhalb der Kerne verbunden
Patterns of dominant flows in the world trade web
The large-scale organization of the world economies is exhibiting
increasingly levels of local heterogeneity and global interdependency.
Understanding the relation between local and global features calls for
analytical tools able to uncover the global emerging organization of the
international trade network. Here we analyze the world network of bilateral
trade imbalances and characterize its overall flux organization, unraveling
local and global high-flux pathways that define the backbone of the trade
system. We develop a general procedure capable to progressively filter out in a
consistent and quantitative way the dominant trade channels. This procedure is
completely general and can be applied to any weighted network to detect the
underlying structure of transport flows. The trade fluxes properties of the
world trade web determines a ranking of trade partnerships that highlights
global interdependencies, providing information not accessible by simple local
analysis. The present work provides new quantitative tools for a dynamical
approach to the propagation of economic crises
A highly stable atomic vector magnetometer based on free spin precession
We present a magnetometer based on optically pumped Cs atoms that measures
the magnitude and direction of a 1 T magnetic field. Multiple circularly
polarized laser beams were used to probe the free spin precession of the Cs
atoms. The design was optimized for long-time stability and achieves a scalar
resolution better than 300 fT for integration times ranging from 80 ms to 1000
s. The best scalar resolution of less than 80 fT was reached with integration
times of 1.6 to 6 s. We were able to measure the magnetic field direction with
a resolution better than 10 rad for integration times from 10 s up to 2000
s
Global Networks of Trade and Bits
Considerable efforts have been made in recent years to produce detailed
topologies of the Internet. Although Internet topology data have been brought
to the attention of a wide and somewhat diverse audience of scholars, so far
they have been overlooked by economists. In this paper, we suggest that such
data could be effectively treated as a proxy to characterize the size of the
"digital economy" at country level and outsourcing: thus, we analyse the
topological structure of the network of trade in digital services (trade in
bits) and compare it with that of the more traditional flow of manufactured
goods across countries. To perform meaningful comparisons across networks with
different characteristics, we define a stochastic benchmark for the number of
connections among each country-pair, based on hypergeometric distribution.
Original data are thus filtered by means of different thresholds, so that we
only focus on the strongest links, i.e., statistically significant links. We
find that trade in bits displays a sparser and less hierarchical network
structure, which is more similar to trade in high-skill manufactured goods than
total trade. Lastly, distance plays a more prominent role in shaping the
network of international trade in physical goods than trade in digital
services.Comment: 25 pages, 6 figure
The International-Trade Network: Gravity Equations and Topological Properties
This paper begins to explore the determinants of the topological properties
of the international - trade network (ITN). We fit bilateral-trade flows using
a standard gravity equation to build a "residual" ITN where trade-link weights
are depurated from geographical distance, size, border effects, trade
agreements, and so on. We then compare the topological properties of the
original and residual ITNs. We find that the residual ITN displays, unlike the
original one, marked signatures of a complex system, and is characterized by a
very different topological architecture. Whereas the original ITN is
geographically clustered and organized around a few large-sized hubs, the
residual ITN displays many small-sized but trade-oriented countries that,
independently of their geographical position, either play the role of local
hubs or attract large and rich countries in relatively complex
trade-interaction patterns
Measurement of the permanent electric dipole moment of the neutron
We present the result of an experiment to measure the electric dipole moment EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons (UCN). Our measurement stands in the long history of EDM experiments probing physics violating time reversal invariance. The salient features of this experiment
were the use of a Hg-199 co-magnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic field changes. The statistical analysis was performed on blinded datasets by two separate groups while the estimation of systematic effects profited from an
unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is d_{\rm n} = (0.0\pm1.1_{\rm stat}\pm0.2_{\rmsys})\times10^{-26}e\,{\rm cm}
Statistical sensitivity of the nEDM apparatus at PSI to n - n' oscillations
The neutron and its hypothetical mirror counterpart, a sterile state degenerate in mass, could spontaneously mix in a process much faster than the neutron ÎČ-decay. Two groups have performed a series of experiments in search of neutron - mirror-neutron (n â n')oscillations. They reported no evidence, thereby setting stringent limits on the oscillation time Ïnn. Later, these data sets have been further analyzed by Berezhiani et al.(2009-2017), and signals, compatible with n - n' oscillations in the presence of mirror magnetic fields, have been reported. The Neutron Electric Dipole Moment Collaboration based at the Paul Scherrer Institute performed a new series of experiments to further test these signals. In this paper, we describe and motivate our choice of run configurations with an optimal filling time of 29 s, storage times of 180 s and 380 s, and applied magnetic fields of 10 ”T and 20 ”T. The choice of these run configurations ensures a reliable overlap in settings with the previous efforts and also improves the sensitivity to test the signals. We also elaborate on the technique of normalizing the neutron counts, making such a counting experiment at the ultra-cold neutron source at the Paul Scherrer Institute possible. Furthermore, the magnetic field characterization to meet the requirements of this n â n oscillation search is demonstrated. Finally, we show that this effort has a statistical sensitivity to n â n' oscillations comparable to the current leading constraints for B' = 0
The n2EDM experiment at the Paul Scherrer Institute
We present the new spectrometer for the neutron electric dipole moment (nEDM) search at the Paul Scherrer Institute (PSI), called n2EDM. The setup is at room temperature in vacuum using ultracold neutrons. n2EDM features a large UCN double storage chamber design with neutron transport adapted to the PSI UCN source. The design builds on experience gained from the previous apparatus operated at PSI until 2017. An order of magnitude increase in sensitivity is calculated for the new baseline setup based on scalable results from the previous apparatus, and the UCN source performance achieved in 2016
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