5,014 research outputs found
Modulated Information Flows in Financial Markets
We model continuous-time information flows generated by a number of
information sources that switch on and off at random times. By modulating a
multi-dimensional L\'evy random bridge over a random point field, our framework
relates the discovery of relevant new information sources to jumps in
conditional expectation martingales. In the canonical Brownian random bridge
case, we show that the underlying measure-valued process follows jump-diffusion
dynamics, where the jumps are governed by information switches. The dynamic
representation gives rise to a set of stochastically-linked Brownian motions on
random time intervals that capture evolving information states, as well as to a
state-dependent stochastic volatility evolution with jumps. The nature of
information flows usually exhibits complex behaviour, however, we maintain
analytic tractability by introducing what we term the effective and
complementary information processes, which dynamically incorporate active and
inactive information, respectively. As an application, we price a financial
vanilla option, which we prove is expressed by a weighted sum of option values
based on the possible state configurations at expiry. This result may be viewed
as an information-based analogue of Merton's option price, but where
jump-diffusion arises endogenously. The proposed information flows also lend
themselves to the quantification of asymmetric informational advantage among
competitive agents, a feature we analyse by notions of information geometry.Comment: 27 pages, 1 figur
The cosmological BCS mechanism and the Big Bang Singularity
We provide a novel mechanism that resolves the Big Bang Singularity present
in FRW space-times without the need for ghost fields. Building on the fact that
a four-fermion interaction arises in General Relativity when fermions are
covariantly coupled, we show that at early times the decrease in scale factor
enhances the correlation between pairs of fermions. This enhancement leads to a
BCS-like condensation of the fermions and opens a gap dynamically driving the
Hubble parameter to zero and results in a non-singular bounce, at least in
some special cases.Comment: replaced to match the journal versio
Nucleosynthesis in the early history of the solar system
Nucleosynthesis in early history of solar syste
The red rain phenomenon of Kerala and its possible extraterrestrial origin
A red rain phenomenon occurred in Kerala, India starting from 25th July 2001,
in which the rainwater appeared coloured in various localized places that are
spread over a few hundred kilometers in Kerala. Maximum cases were reported
during the first 10 days and isolated cases were found to occur for about 2
months. The striking red colouration of the rainwater was found to be due to
the suspension of microscopic red particles having the appearance of biological
cells. These particles have no similarity with usual desert dust. An estimated
minimum quantity of 50,000 kg of red particles has fallen from the sky through
red rain. An analysis of this strange phenomenon further shows that the
conventional atmospheric transport processes like dust storms etc. cannot
explain this phenomenon. The electron microscopic study of the red particles
shows fine cell structure indicating their biological cell like nature. EDAX
analysis shows that the major elements present in these cell like particles are
carbon and oxygen. Strangely, a test for DNA using Ethidium Bromide dye
fluorescence technique indicates absence of DNA in these cells. In the context
of a suspected link between a meteor airburst event and the red rain, the
possibility for the extraterrestrial origin of these particles from cometary
fragments is discussed.Comment: 18 pages, 15 figures, accepted for publication in Astrophysics and
Space Scienc
Implications of multiple high-redshift galaxy clusters
To date, 14 high-redshift (z>1.0) galaxy clusters with mass measurements have
been observed, spectroscopically confirmed and are reported in the literature.
These objects should be exceedingly rare in the standard LCDM model. We
conservatively approximate the selection functions of these clusters' parent
surveys, and quantify the tension between the abundances of massive clusters as
predicted by the standard LCDM model and the observed ones. We alleviate the
tension considering non-Gaussian primordial perturbations of the local type,
characterized by the parameter fnl and derive constraints on fnl arising from
the mere existence of these clusters. At the 95% confidence level, fnl>467 with
cosmological parameters fixed to their most likely WMAP5 values, or fnl > 123
(at 95% confidence) if we marginalize over WMAP5 parameters priors. In
combination with fnl constraints from Cosmic Microwave Background and halo
bias, this determination implies a scale-dependence of fnl at approx. 3 sigma.
Given the assumptions made in the analysis, we expect any future improvements
to the modeling of the non-Gaussian mass function, survey volumes, or selection
functions to increase the significance of fnl>0 found here. In order to
reconcile these massive, high-z clusters with an fnl=0, their masses would need
to be systematically lowered by 1.5 sigma or the sigma8 parameter should be
approx. 3 sigma higher than CMB (and large-scale structure) constraints. The
existence of these objects is a puzzle: it either represents a challenge to the
LCDM paradigme or it is an indication that the mass estimates of clusters is
dramatically more uncertain than we think.Comment: 11 pages, 7 figures, modified to match published versio
What and how: doing good research with young people, digital intimacies, and relationships and sex education
© 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. As part of a project funded by the Wellcome Trust, we held a one-day symposium, bringing together researchers, practitioners, and policymakers, to discuss priorities for research on relationships and sex education (RSE) in a world where young people increasingly live, experience, and augment their relationships (whether sexual or not) within digital spaces. The introduction of statutory RSE in schools in England highlights the need to focus on improving understandings of young people and digital intimacies for its own sake, and to inform the development of learning resources. We call for more research that puts young people at its centre; foregrounds inclusivity; and allows a nuanced discussion of pleasures, harms, risks, and rewards, which can be used by those working with young people and those developing policy. Generating such research is likely to be facilitated by participation, collaboration, and communication with beneficiaries, between disciplines and across sectors. Taking such an approach, academic researchers, practitioners, and policymakers agree that we need a better understanding of RSE’s place in lifelong learning, which seeks to understand the needs of particular groups, is concerned with non-sexual relationships, and does not see digital intimacies as disconnected from offline everyday ‘reality’
First Occurrence of Chain Pickerel (Esox niger) in Ontario: Possible Range Expansion from New York Waters of Eastern Lake Ontario
In this paper, we document the first Chain Pickerel (Esox niger) collected in Ontario and the first on the northwestern side of the St. Lawrence River in Canada. The fish was caught by a local commercial fisherman in April 2008. Since 2008, five additional specimens have been caught and are also documented here: three in 2009 and two more through spring 2010. All individuals were mature adults in robust condition. The appearance of Chain Pickerel in the Ontario waters of eastern Lake Ontario and the upper St. Lawrence River may signal an expansion in the range of this species from New York state waters
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