15,263 research outputs found
Pion and Kaon Masses and Pion Form Factors from Dynamical Chiral-Symmetry Breaking with Light Constituent Quarks
Light constituent quark masses and the corresponding dynamical quark masses
are determined by data, the quark-level linear sigma model, and infrared QCD.
This allows to define effective nonstrange and strange current quark masses,
which reproduce the experimental pion and kaon masses very accurately, by
simple additivity. In contrast, the usual nonstrange and strange current quarks
employed by the Particle Data Group and Chiral Perturbation Theory do not allow
a straightforward quantitative explanation of the pion and kaon masses.Comment: 4 pages, AIP style, contribution to conference ``Quark Confinement
and the Hadron Spectrum VII'', Azores, Portugal, 2-7 September 200
Why the f(0)(980) is mostly ssbar
We exploit the W-emission process to study the measured weak decay of the
D(s,+)(1.9686) meson into f(0)(980) and a positively charged pion. We conclude
that the scalar f(0)(980) meson contains mostly strange-antistrange flavors,
which is supported by different model studies.Comment: 5 pages, plain LaTeX, minor changes, acknowledgment
Transfer learning approach for financial applications
Artificial neural networks learn how to solve new problems through a
computationally intense and time consuming process. One way to reduce the
amount of time required is to inject preexisting knowledge into the network. To
make use of past knowledge, we can take advantage of techniques that transfer
the knowledge learned from one task, and reuse it on another (sometimes
unrelated) task. In this paper we propose a novel selective breeding technique
that extends the transfer learning with behavioural genetics approach proposed
by Kohli, Magoulas and Thomas (2013), and evaluate its performance on financial
data. Numerical evidence demonstrates the credibility of the new approach. We
provide insights on the operation of transfer learning and highlight the
benefits of using behavioural principles and selective breeding when tackling a
set of diverse financial applications problems
Advisor Choice in Asia-Pacific Property Markets
This paper examines advisor choice decisions by publicly traded REITs and listed property companies in Asia-Pacific real estate markets. Using a sample of 168 firms, we find robust evidence that firms strategically evaluate and compare the increased agency costs associated with external advisement against the potential benefits associated with collocating decision rights with location specific soft information. Our empirical results reveal real estate companies tend to hire external advisors when they invest in countries: 1) that are more economically and politically unstable, 2) whose legal system is based on civil law, 3) where the level of corruption is perceived to be high, and 4) when disclosure is relatively poor. Additionally, we find the probability of retaining an external advisor is directly related to the expected agency costs. Lastly, we find evidence of return premiums in excess of 13 % for firms whose organizational structure matches their investment profile. As such, we conclude that the decision to hire an external advisor represents a value relevant trade-off between the costs and benefits of this organizational arrangement
Capital Structure and Political Risk in Asia-Pacific Real Estate Markets
This study investigates the determinants of capital structure decisions by real estate firms, with a specific focus on the impact of political risk on leverage. Using a sample of Asia-Pacific REITs and listed property trusts, we find those firms with properties located in countries characterized by relatively high degrees of political risk, such as political instability, and/or greater uncertainty in the ability to repatriate and monetize profits from international investment activities, employ less debt than their counterparts operating in more politically stable environments. This core finding remains robust to alternative sample selection criteria including the division of the sample into high versus low market-to-book value firms, and also holds within the subset of organizations that are active in raising additional capital in the secondary markets
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