The determinants of option-adjusted delta credit spreads: a comparative analysis of the United States, the United Kingdom and the euro area

We analyse the determinants of the variation of option-adjusted credit spreads (OASs) on a unique database that enlarges the traditional scope of analysis to more disaggregated indexes (combining industry, grade and maturity levels), new variables (volumes of sales and purchases of institutional investors) and a complete set of markets (besides the United States, the United Kingdom and the euro area). With our extended set of regressors we explain almost half of the variability of OASs and find evidence of a significant impact of institutional investors’ purchases and sales on corporate bond risk. We also find that US business cycle indicators significantly affect the variability of OASs in the United Kingdom and the euro area.option-adjusted credit spreads; delta; corporate bond risk; institutional investors; business cycle indicators

The determinants of option adjusted delta credit spreads: A comparative analysis on US, UK and the Eurozone

We analyse the determinants of the variation of option adjusted credit spreads (OASs) on a unique database which enlarges the traditional scope of the analysis to more disaggregated indexes (combining industry, grade and maturity levels), new variables (volumes of sales and purchases of institutional investors) and a complete set of markets (beside US, UK and the Eurozone). With our extended set of regressors we explain almost half of the variability of OASs and we find evidence of the significant impact of institutional investors' purchases and sales on corporate bond risk. We also find that US business cycle indicators significantly affect the variability of OASs in the UK and in the Eurozone.

Ion Channels in Hematopoietic and Mesenchymal Stem Cells

Hematopoietic stem cells (HSCs) reside in bone marrow niches and give rise to hematopoietic precursor cells (HPCs). These have more restricted lineage potential and eventually differentiate into specific blood cell types. Bone marrow also contains mesenchymal stromal cells (MSCs), which present multilineage differentiation potential toward mesodermal cell types. In bone marrow niches, stem cell interaction with the extracellular matrix is mediated by integrin receptors. Ion channels regulate cell proliferation and differentiation by controlling intracellular Ca2+, cell volume, release of growth factors, and so forth. Although little evidence is available about the ion channel roles in true HSCs, increasing information is available about HPCs and MSCs, which present a complex pattern of K+ channel expression. K+ channels cooperate with Ca2+ and Cl− channels in regulating calcium entry and cell volume during mitosis. Other K+ channels modulate the integrin-dependent interaction between leukemic progenitor cells and the niche stroma. These channels can also regulate leukemia cell interaction with MSCs, which also involves integrin receptors and affects the MSC-mediated protection from chemotherapy. Ligand-gated channels are also implicated in these processes. Nicotinic acetylcholine receptors regulate cell proliferation and migration in HSCs and MSCs and may be implicated in the harmful effects of smoking

Self-Stabilizing Repeated Balls-into-Bins

We study the following synchronous process that we call "repeated balls-into-bins". The process is started by assigning $n$ balls to $n$ bins in an arbitrary way. In every subsequent round, from each non-empty bin one ball is chosen according to some fixed strategy (random, FIFO, etc), and re-assigned to one of the $n$ bins uniformly at random. We define a configuration "legitimate" if its maximum load is $\mathcal{O}(\log n)$. We prove that, starting from any configuration, the process will converge to a legitimate configuration in linear time and then it will only take on legitimate configurations over a period of length bounded by any polynomial in $n$, with high probability (w.h.p.). This implies that the process is self-stabilizing and that every ball traverses all bins in $\mathcal{O}(n \log^2 n)$ rounds, w.h.p

Stabilizing Consensus with Many Opinions

We consider the following distributed consensus problem: Each node in a complete communication network of size $n$ initially holds an \emph{opinion}, which is chosen arbitrarily from a finite set $\Sigma$. The system must converge toward a consensus state in which all, or almost all nodes, hold the same opinion. Moreover, this opinion should be \emph{valid}, i.e., it should be one among those initially present in the system. This condition should be met even in the presence of an adaptive, malicious adversary who can modify the opinions of a bounded number of nodes in every round. We consider the \emph{3-majority dynamics}: At every round, every node pulls the opinion from three random neighbors and sets his new opinion to the majority one (ties are broken arbitrarily). Let $k$ be the number of valid opinions. We show that, if $k \leqslant n^{\alpha}$, where $\alpha$ is a suitable positive constant, the 3-majority dynamics converges in time polynomial in $k$ and $\log n$ with high probability even in the presence of an adversary who can affect up to $o(\sqrt{n})$ nodes at each round. Previously, the convergence of the 3-majority protocol was known for $|\Sigma| = 2$ only, with an argument that is robust to adversarial errors. On the other hand, no anonymous, uniform-gossip protocol that is robust to adversarial errors was known for $|\Sigma| > 2$

Master Integrals for the two-loop, non-planar QCD corrections to top-quark pair production in the quark-annihilation channel

We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of differential equations, we expand the integrals in powers of the dimensional regulator $\epsilon$ and determine the expansion coefficients in terms of generalized harmonic polylogarithms of two dimensionless variables through to weight four.Comment: 28 pages, 2 figures, ancillary files include