2,859 research outputs found
Liquidity Hoarding and Interbank Market Spreads: The Role of Counterparty Risk
We study the functioning and possible breakdown of the interbank market due to asymmetric information about counterparty risk. We allow for privately observed shocks to the distribution of asset risk across banks after the initial portfolio of liquid and illiquid investments is chosen. Our model generates sev- eral interbank market regimes: 1) low interest rate spread and full participation; 2) elevated spread and adverse selection; and 3) liquidity hoarding leading to a market breakdown. The regimes are in line with observed developments in the interbank market before and during the 2007-09 financial crisis. We use the model to examine various policy responses.Financial crisis;Interbank market;Liquidity;Asymmetric in- formation
A Study Abroad Program in Tanzania: The Evolution of Social Justice Action Work
This article focuses on the evolution of our study abroad program to Tanzania, including the integration of three liberal arts disciplines and the foundational core that links together the three areas: social justice activism. More specifically, we explore the overall challenge of dismantling âus versus themâ thinking and the interactive learning moments that allow this process to transpire. We narrate how what we learned on our 2008 and our 2010 trips led to our model of social justice action work, which we enacted on our 2012 trip. Our approach to social justice action work integrates experiential learning with Dan Butinâs concept of âjustice learning,â or education that interrupts and complicates binary thinking. Our three-fold model encompasses teaching moments where instructors create the academic framework to facilitate change in our students, where students observe grass-roots organizations performing âtraditionalâ social justice action work, and where on-site activities generate interactive experiential moments in which perceptions can be changed
Liquidity Hoarding and Interbank Market Spreads:The Role of Counterparty Risk
We study the functioning and possible breakdown of the interbank market due to asymmetric information about counterparty risk. We allow for privately observed shocks to the distribution of asset risk across banks after the initial portfolio of liquid and illiquid investments is chosen. Our model generates sev- eral interbank market regimes: 1) low interest rate spread and full participation; 2) elevated spread and adverse selection; and 3) liquidity hoarding leading to a market breakdown. The regimes are in line with observed developments in the interbank market before and during the 2007-09 financial crisis. We use the model to examine various policy responses
Multirelational Organization of Large-scale Social Networks in an Online World
The capacity to collect fingerprints of individuals in online media has
revolutionized the way researchers explore human society. Social systems can be
seen as a non-linear superposition of a multitude of complex social networks,
where nodes represent individuals and links capture a variety of different
social relations. Much emphasis has been put on the network topology of social
interactions, however, the multi-dimensional nature of these interactions has
largely been ignored in empirical studies, mostly because of lack of data.
Here, for the first time, we analyze a complete, multi-relational, large social
network of a society consisting of the 300,000 odd players of a massive
multiplayer online game. We extract networks of six different types of
one-to-one interactions between the players. Three of them carry a positive
connotation (friendship, communication, trade), three a negative (enmity, armed
aggression, punishment). We first analyze these types of networks as separate
entities and find that negative interactions differ from positive interactions
by their lower reciprocity, weaker clustering and fatter-tail degree
distribution. We then proceed to explore how the inter-dependence of different
network types determines the organization of the social system. In particular
we study correlations and overlap between different types of links and
demonstrate the tendency of individuals to play different roles in different
networks. As a demonstration of the power of the approach we present the first
empirical large-scale verification of the long-standing structural balance
theory, by focusing on the specific multiplex network of friendship and enmity
relations.Comment: 7 pages, 5 figures, accepted for publication in PNA
Interpol: An R package for preprocessing of protein sequences
<p>Abstract</p> <p>Background</p> <p>Most machine learning techniques currently applied in the literature need a fixed dimensionality of input data. However, this requirement is frequently violated by real input data, such as DNA and protein sequences, that often differ in length due to insertions and deletions. It is also notable that performance in classification and regression is often improved by numerical encoding of amino acids, compared to the commonly used sparse encoding.</p> <p>Results</p> <p>The software "Interpol" encodes amino acid sequences as numerical descriptor vectors using a database of currently 532 descriptors (mainly from AAindex), and normalizes sequences to uniform length with one of five linear or non-linear interpolation algorithms. Interpol is distributed with open source as platform independent R-package. It is typically used for preprocessing of amino acid sequences for classification or regression.</p> <p>Conclusions</p> <p>The functionality of Interpol widens the spectrum of machine learning methods that can be applied to biological sequences, and it will in many cases improve their performance in classification and regression.</p
Wisconsin Farmers Take the 2-Pass Challenge Against Weeds
Single pass herbicide programs have become the standard for most Wisconsin corn producers. The apparent time and cost savings in controlling weeds with a single pre or post-emergence herbicide application is the driving force behind this trend. While there are situations where a single pass program will work, it has weaknesses that can result in inconsistent performance
Dynamics of Social Balance on Networks
We study the evolution of social networks that contain both friendly and
unfriendly pairwise links between individual nodes. The network is endowed with
dynamics in which the sense of a link in an imbalanced triad--a triangular loop
with 1 or 3 unfriendly links--is reversed to make the triad balanced. With this
dynamics, an infinite network undergoes a dynamic phase transition from a
steady state to "paradise"--all links are friendly--as the propensity p for
friendly links in an update event passes through 1/2. A finite network always
falls into a socially-balanced absorbing state where no imbalanced triads
remain. If the additional constraint that the number of imbalanced triads in
the network does not increase in an update is imposed, then the network quickly
reaches a balanced final state.Comment: 10 pages, 7 figures, 2-column revtex4 forma
Kink far below the Fermi level reveals new electron-magnon scattering channel in Fe
Many properties of real materials can be modeled using ab initio methods
within a single-particle picture. However, for an accurate theoretical
treatment of excited states, it is necessary to describe electron-electron
correlations including interactions with bosons: phonons, plasmons, or magnons.
In this work, by comparing spin- and momentum-resolved photoemission
spectroscopy measurements to many-body calculations carried out with a newly
developed first-principles method, we show that a kink in the electronic band
dispersion of a ferromagnetic material can occur at much deeper binding
energies than expected (E_b=1.5 eV). We demonstrate that the observed spectral
signature reflects the formation of a many-body state that includes a photohole
bound to a coherent superposition of renormalized spin-flip excitations. The
existence of such a many-body state sheds new light on the physics of the
electron-magnon interaction which is essential in fields such as spintronics
and Fe-based superconductivity.Comment: 6 pages, 2 figure
Optimization of quasi-normal eigenvalues for Krein-Nudelman strings
The paper is devoted to optimization of resonances for Krein strings with
total mass and statical moment constraints. The problem is to design for a
given a string that has a resonance on the line \alpha + \i
\R with a minimal possible modulus of the imaginary part. We find optimal
resonances and strings explicitly.Comment: 9 pages, these results were extracted in a slightly modified form
from the earlier e-print arXiv:1103.4117 [math.SP] following an advise of a
journal's refere
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