760 research outputs found
Asymmetric dynamics in the correlations of global equity and bond returns
JEL Classification: F3, G1, C5Correlation, International Finance, Variance Targeting
Prescriptions for Off-Shell Bosonic String Amplitudes
We give, in the framework of the bosonic string theory, simple prescriptions
for computing, at tree and one-loop levels, off-shell string amplitudes for
open and closed string massless states. In particular we obtain a tree
amplitude for three open strings that in the field theory limit coincides with
the three-gluon vertex in the usual covariant gauge and two-string one-loop
amplitudes satisfying the property of transversality.Comment: 11 pages, LaTeX, to appear in the proceedings of the workshop
"Quantum Aspects of Gauge Theories, Supersymmetry and Unification", Corfu
(Greece), 20-26 September 1998. Eq. (12) and numerical factors in eqs. (13)
and (16) corrected; some minor changes and references adde
Form factor in K+ --> pi+ pi0 gamma: interference versus direct emission
We analyze the effect of a form factor in the magnetic contribution to K+ -->
pi+ pi0 gamma. We emphasize how this can show up experimentally: in particular
we try to explore the difference between a possible interference contribution
and a form factor in the magnetic part. The form factor used for K+ --> pi+ pi0
gamma is analogous to the one for KL --> pi+ pi- gamma, experimentally well
established.Comment: 9 pages revtex, 10 eps figures; improved presentation of theoretical
and experimental status; refs. adde
Experiments and analysis of quality andEnergy-aware data aggregation approaches inWSNs
A wireless sensor network consists of autonomous devices
able to collect various data from the area that surrounds
them. However, the resources associated with sensors are
limited and, thus, in order to guarantee a longer life of all
the network components, it is necessary to adopt energysavings
methods. This paper, considering that the transmission
phase is the main cause of energy dissipation, presents
an approach aimed to save energy by capturing and aggregating
signals instead of sending them in raw form. Anyway,
aggregation should not imply the loss of useful data. For this
reason, information about possible outliers is preserved and
the aggregated values have to satisfy data quality (i.e., accuracy,
precision, and timeliness) requirements. In order to
show the correctness and validity of the proposed method,
it has been tested on a real case study and its performance
has been compared with two other consolidated approaches
The hadronic light by light contribution to the with holographic models of QCD
We study the anomalous electromagnetic pion form factor
with a set of holographic models. By comparing with
the measured value of the linear slope, some of these models can be ruled out.
From the remaining models we obtain predictions for the low-energy quadratic
slope parameters of , currently out of experimental
reach but testable in the near future. We find it particularly useful to encode
this low-energy information in a form factor able to satisfy also QCD
short-distance constraints. We choose the form factor introduced by D'Ambrosio,
Isidori and Portoles in kaon decays, which has the right short distance for a
particular value of the quadratic slope, which is later shown to be compatible
with our holographic predictions. We then turn to a determination of the
(dominant) pion exchange diagram in the hadronic light by light scattering
contribution to the muon anomalous magnetic moment. We quantify the theoretical
uncertainty in coming from the different input we use: QCD short
distances, experimental input and low-energy holographic predictions. We also
test the pion-pole approximation. Our final result is
, where the error is driven by the
linear slope of , soon to be measured with precision
at KLOE-2. Our numerical analysis also indicates that large values of the
magnetic susceptibility are disfavored, therefore pointing at a mild
effect from the pion off-shellness. However, in the absence of stronger bounds
on , an additional systematic uncertainty on the previous
value for cannot be excluded.Comment: 20 pages, 5 figures. Substantial improvements throughout the text to
match the published version. Enhanced discussion of the analysis in Section
IV with the addition of two appendices. Conclusions unchange
Live, Personal Data Integration Through UI-Oriented Computing
This paper proposes a new perspective on the problem of data integration on the Web: the one of the Surface Web. It introduces the concept of UI-oriented computing as a computing paradigm whose core ingredient are the user interfaces that build up the SurfaceWeb, and shows how a sensible mapping of data integration tasks to user interface elements and user interactions is able to cope with data integration scenarios that so far have only be conceived for the Deep Web with its APIs and Web services. The described approach provides a novel conceptual and technological framework for practices, such as the integration of data APIs/services and the extraction of content from Web pages, that are common practice but still not adequately supported. The approach targets both programmers and users alike and comes as an extensible, open-source browser extension
Determinants of insurance companies' enviromental, social, and governance awareness
Environmental, social, and governance (ESG) criteria are increasingly important in all fields of economics. However, despite increasing interest from policy makers and financial regulators, literature relating to the insurance industry is still scarce. This paper aims to fill this gap by exploring the interaction between a set of financial ratios and environmental social governance scores of 107 large, listed US insurance companies for the period 2010–2018 for the purpose of identifying the determinants of ESG awareness. Larger, more profitable, and more solvent insurance companies show the highest level of ESG awareness. Our model contributes to shed light on the unfolding of ESG practices in the insurance industry
Off-shell amplitudes for nonoriented closed strings
In the context of the bosonic closed string theory, by using the operatorial formalism, we give a simple expression of the off-shell amplitude with an arbitrary number of external massless states inserted on the Klein bottle
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