7,198 research outputs found
On the super replication price of unbounded claims
In an incomplete market the price of a claim f in general cannot be uniquely
identified by no arbitrage arguments. However, the ``classical'' super
replication price is a sensible indicator of the (maximum selling) value of the
claim. When f satisfies certain pointwise conditions (e.g., f is bounded from
below), the super replication price is equal to sup_QE_Q[f], where Q varies on
the whole set of pricing measures. Unfortunately, this price is often too high:
a typical situation is here discussed in the examples. We thus define the less
expensive weak super replication price and we relax the requirements on f by
asking just for ``enough'' integrability conditions. By building up a proper
duality theory, we show its economic meaning and its relation with the
investor's preferences. Indeed, it turns out that the weak super replication
price of f coincides with sup_{Q\in M_{\Phi}}E_Q[f], where M_{\Phi} is the
class of pricing measures with finite generalized entropy (i.e., E[\Phi
(\frac{dQ}{dP})]<\infty) and where \Phi is the convex conjugate of the utility
function of the investor.Comment: Published at http://dx.doi.org/10.1214/105051604000000459 in the
Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute
of Mathematical Statistics (http://www.imstat.org
A unified framework for utility maximization problems: An Orlicz space approach
We consider a stochastic financial incomplete market where the price
processes are described by a vector-valued semimartingale that is possibly
nonlocally bounded. We face the classical problem of utility maximization from
terminal wealth, with utility functions that are finite-valued over
, , and satisfy weak regularity
assumptions. We adopt a class of trading strategies that allows for stochastic
integrals that are not necessarily bounded from below. The embedding of the
utility maximization problem in Orlicz spaces permits us to formulate the
problem in a unified way for both the cases and .
By duality methods, we prove the existence of solutions to the primal and dual
problems and show that a singular component in the pricing functionals may also
occur with utility functions finite on the entire real line.Comment: Published in at http://dx.doi.org/10.1214/07-AAP469 the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Early Gabapentin Treatment during the Latency Period Increases Convulsive Threshold, Reduces Microglial Activation and Macrophage Infiltration in the Lithium-Pilocarpine Model of Epilepsy
The lithium-pilocarpine model of epilepsy reproduces several features of temporal lobe epilepsy in humans, including the chronological timeline of an initial latency period followed by the development of spontaneous seizures. Epilepsy therapies in humans are implemented, as a rule, after the onset of the spontaneous seizures. We here studied the potential effect on epileptogenesis of starting an early treatment during the latency period, in order to prevent the development of spontaneous seizures. Adult male Wistar rats were treated with 3 mEq/kg LiCl, and 20 h later 30 mg/kg pilocarpine. Once status epilepticus (SE) was achieved, it was allowed to last for 20 min, and then motor seizures were controlled with the administration of 20 mg/kg diazepam. At 1DPSE (DPSE, days post-status epilepticus), animals started to receive 400 mg/kg/day gabapentin or saline for 4 days. At 5DPSE, we observed that SE induced an early profuse microglial and astroglial reactivity, increased synaptogenic trombospondin-1 expression and reduced AQP4 expression in astroglial ending feet. Blood brain barrier (BBB) integrity seemed to be compromised, as infiltrating NG2+ macrophages and facilitated access to the CNS was observed by transplanting eGFP+ blood cells and bone marrow-derived progenitors in the SE animals. The early 4-day gabapentin treatment successfully reduced microglial cell reactivity and blood-borne cell infiltration, without significantly altering the mRNA of proinflammatory cytokines IL-1β and TNFα immediately after the treatment. After 21DSPE, another group of animals that developed SE and received 4 days of gabapentin treatment, were re-exposed to subconvulsive accumulative doses of pilocarpine (10 mg/kg/30 min) and were followed by recording the Racine scale reached. Early 4-day gabapentin treatment reduced the Racine scale reached by the animals, reduced animal mortality, and reduced the number of animals that achieved SE (34% vs. 72%). We conclude that early gabapentin treatment following SE, during the latency period, is able to reduce neuroinflammation and produces a persistent effect that limits seizures and increases convulsive threshold, probably by restricting microglial reactivity and spurious synaptogenesis.Fil: Rossi, Alicia Raquel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia ; ArgentinaFil: Murta, Verónica. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia ; ArgentinaFil: Auzmendi, Jerónimo Andrés. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia ; ArgentinaFil: Ramos, Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de BiologÃa Celular y Neurociencia ; Argentin
Status of the Super-B factory Design
The SuperB international team continues to optimize the design of an
electron-positron collider, which will allow the enhanced study of the origins
of flavor physics. The project combines the best features of a linear collider
(high single-collision luminosity) and a storage-ring collider (high repetition
rate), bringing together all accelerator physics aspects to make a very high
luminosity of 10 cm sec. This asymmetric-energy collider
with a polarized electron beam will produce hundreds of millions of B-mesons at
the (4S) resonance. The present design is based on extremely low
emittance beams colliding at a large Piwinski angle to allow very low
without the need for ultra short bunches. Use of crab-waist
sextupoles will enhance the luminosity, suppressing dangerous resonances and
allowing for a higher beam-beam parameter. The project has flexible beam
parameters, improved dynamic aperture, and spin-rotators in the Low Energy Ring
for longitudinal polarization of the electron beam at the Interaction Point.
Optimized for best colliding-beam performance, the facility may also provide
high-brightness photon beams for synchrotron radiation applications
Spartan Daily, November 8, 2004
Volume 123, Issue 49https://scholarworks.sjsu.edu/spartandaily/10053/thumbnail.jp
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The Emerging Role of Ten-Eleven Translocation 1 in Epigenetic Responses to Environmental Exposures.
Mounting evidence from epidemiological studies and animal models has linked exposures to environmental factors to changes in epigenetic markers, especially in DNA methylation. These epigenetic changes may lead to dysregulation of molecular processes and functions and mediate the impact of environmental exposures in complex diseases. However, detailed molecular events that result in epigenetic changes following exposures remain unclear. Here, we review the emerging evidence supporting a critical role of ten-eleven translocation 1 (TET1) in mediating these processes. Targeting TET1 and its associated pathways may have therapeutic potential in alleviating negative impacts of environmental exposures, preventing and treating exposure-related diseases
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