4,411 research outputs found
The financial situation of non-financial corporations
As entities where the production process takes place, non financial corporations deserve full attention in the analysis of the real and financial accounts. However, the examination of the financial behaviour of non financial corporations is traditionally confined to their financing : thus, the Bank’s annual report generally only considers their liabilities. Yet the formation of financial assets by non financial corporations is a significant item of information, in both statistical and economic terms. The total financial assets held by non financial corporations in Belgium are considerable, as they far exceed the total financial assets of households. A study recently revealed the historically high level of financial asset formation by non financial corporations in the main industrialised countries, a factor which could help to explain the relatively low level of long-term interest rates. In recent years, Belgian non financial corporations have formed substantially more financial assets than their counterparts in the euro area. In 2005, the financial assets held by Belgian companies were – partly for that reason – almost double the financial assets, expressed in percentages of GDP, of non financial corporations in the euro area. However, this situation certainly does not indicate any risk aversion on the part of Belgian non financial corporations. In fact the liabilities side of their balance sheets also records growth of new financial liabilities in excess of the figure for non financial corporations in the euro area, so that – in terms of liabilities, too – the outstanding total in Belgium is comparatively much higher than the outstanding total in the euro area. This paradoxical situation of Belgian non financial corporations – the fact that they hold much more substantial assets while at the same time contracting significantly greater liabilities – is due to the fact that the Belgian non financial corporations sector includes coordination centres and non financial holding companies, i.e. undertakings acting, as it were, as financial intermediaries. If the coordination centres and non financial holding companies are excluded, the overall outstanding total gross assets and liabilities of Belgian non financial corporations reverts to a level very close to the figure for the euro area. Finally, in 2005 Belgian non financial institutions recorded an outstanding total of net liabilities amounting to around 100 p.c. of GDP, i.e. slightly more than the outstanding total for non financial corporations in the euro area. It is also apparent that the exclusion of the coordination centres and non financial holding companies has hardly any effect on Belgium’s net debtor position, confirming that these two types of institutions perform an intermediary function. Although it is not possible to isolate the coordination centres and non financial holding companies in the case of new transactions (flows), there is no reason to think that the effect would be any different : there would be a significant decline in the gross flows of new assets and liabilities, but that would have a negligible influence on the financial balance. That balance is very similar to the one for the euro area.flow of funds, corporate finance
Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) Observed Feeding on Chamaesaracha sp. in Eastern Colorado.
Egg, larval, and adult life stages of Colorado potato beetle, Leptinotarsa decemlineata (Say), were observed feeding on or attached to a previously undocumented host plant belonging to the genus Chamaesaracha in eastern Colorado on July 2017. At one site, L. decemlineata were more abundant on Chamaesaracha sp. than the accepted ancestral host plant, Solanum rostratum (Dunal). While future studies should confirm the ancestral status of the observed L. decemlineata and suitability of Chamaesaracha sp. for completion of development, our observations suggest a need for further characterization of the ancestral host range of L. decemlineata
Engineering stochasticity in gene expression
Stochastic fluctuations (noise) in gene expression can cause members of otherwise genetically identical populations to display drastically different phenotypes. An understanding of the sources of noise and the strategies cells employ to function reliably despite noise is proving to be increasingly important in describing the behavior of natural organisms and will be essential for the engineering of synthetic biological systems. Here we describe the design of synthetic constructs, termed ribosome competing RNAs (rcRNAs), as a means to rationally perturb noise in cellular gene expression. We find that noise in gene expression increases in a manner proportional to the ability of an rcRNA to compete for the cellular ribosome pool. We then demonstrate that operons significantly buffer noise between coexpressed genes in a natural cellular background and can even reduce the level of rcRNA enhanced noise. These results demonstrate that synthetic genetic constructs can significantly affect the noise profile of a living cell and, importantly, that operons are a facile genetic strategy for buffering against noise
Hyperuniformity, quasi-long-range correlations, and void-space constraints in maximally random jammed particle packings. II. Anisotropy in particle shape
We extend the results from the first part of this series of two papers by
examining hyperuniformity in heterogeneous media composed of impenetrable
anisotropic inclusions. Specifically, we consider maximally random jammed
packings of hard ellipses and superdisks and show that these systems both
possess vanishing infinite-wavelength local-volume-fraction fluctuations and
quasi-long-range pair correlations. Our results suggest a strong generalization
of a conjecture by Torquato and Stillinger [Phys. Rev. E. 68, 041113 (2003)],
namely that all strictly jammed saturated packings of hard particles, including
those with size- and shape-distributions, are hyperuniform with signature
quasi-long-range correlations. We show that our arguments concerning the
constrained distribution of the void space in MRJ packings directly extend to
hard ellipse and superdisk packings, thereby providing a direct structural
explanation for the appearance of hyperuniformity and quasi-long-range
correlations in these systems. Additionally, we examine general heterogeneous
media with anisotropic inclusions and show for the first time that one can
decorate a periodic point pattern to obtain a hard-particle system that is not
hyperuniform with respect to local-volume-fraction fluctuations. This apparent
discrepancy can also be rationalized by appealing to the irregular distribution
of the void space arising from the anisotropic shapes of the particles. Our
work suggests the intriguing possibility that the MRJ states of hard particles
share certain universal features independent of the local properties of the
packings, including the packing fraction and average contact number per
particle.Comment: 29 pages, 9 figure
Emergence of heterogeneity and political organization in information exchange networks
We present a simple model of the emergence of the division of labor and the
development of a system of resource subsidy from an agent-based model of
directed resource production with variable degrees of trust between the agents.
The model has three distinct phases, corresponding to different forms of
societal organization: disconnected (independent agents), homogeneous
cooperative (collective state), and inhomogeneous cooperative (collective state
with a leader). Our results indicate that such levels of organization arise
generically as a collective effect from interacting agent dynamics, and may
have applications in a variety of systems including social insects and
microbial communities.Comment: 10 pages, 6 figure
Generic Absorbing Transition in Coevolution Dynamics
We study a coevolution voter model on a network that evolves according to the
state of the nodes. In a single update, a link between opposite-state nodes is
rewired with probability , while with probability one of the nodes
takes its neighbor's state. A mean-field approximation reveals an absorbing
transition from an active to a frozen phase at a critical value
that only depends on the average degree of the
network. The approach to the final state is characterized by a time scale that
diverges at the critical point as . We find that the
active and frozen phases correspond to a connected and a fragmented network
respectively. We show that the transition in finite-size systems can be seen as
the sudden change in the trajectory of an equivalent random walk at the
critical rewiring rate , highlighting the fact that the mechanism behind
the transition is a competition between the rates at which the network and the
state of the nodes evolve.Comment: 5 pages, 4 figure
A Method to Find Community Structures Based on Information Centrality
Community structures are an important feature of many social, biological and
technological networks. Here we study a variation on the method for detecting
such communities proposed by Girvan and Newman and based on the idea of using
centrality measures to define the community boundaries (M. Girvan and M. E. J.
Newman, Community structure in social and biological networks Proc. Natl. Acad.
Sci. USA 99, 7821-7826 (2002)). We develop an algorithm of hierarchical
clustering that consists in finding and removing iteratively the edge with the
highest information centrality. We test the algorithm on computer generated and
real-world networks whose community structure is already known or has been
studied by means of other methods. We show that our algorithm, although it runs
to completion in a time O(n^4), is very effective especially when the
communities are very mixed and hardly detectable by the other methods.Comment: 13 pages, 13 figures. Final version accepted for publication in
Physical Review
Spectral Measures of Bipartivity in Complex Networks
We introduce a quantitative measure of network bipartivity as a proportion of
even to total number of closed walks in the network. Spectral graph theory is
used to quantify how close to bipartite a network is and the extent to which
individual nodes and edges contribute to the global network bipartivity. It is
shown that the bipartivity characterizes the network structure and can be
related to the efficiency of semantic or communication networks, trophic
interactions in food webs, construction principles in metabolic networks, or
communities in social networks.Comment: 16 pages, 1 figure, 1 tabl
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