6,365 research outputs found
Modeling Commercial Processes and Customer Behaviors to Estimate
We propose a formal model for estimating the diffusion rate of a new product on a coherent market. Our approach is based on a discrete probabilistic modeling of customer behaviors and of commercial processes.Diffusion of innovation, diffusion rate, marketing, customer behavior, product diffusion
A 2D nanosphere array for atomic spectroscopy
We are interested in the spectroscopic behaviour of a gas confined in a
micrometric or even nanometric volume. Such a situation could be encountered by
the filling-up of a porous medium, such as a photonic crystal, with an atomic
gas. Here, we discuss the first step of this program, with the generation and
characterization of a self-organized 2D film of nanospheres of silica. We show
that an optical characterization by laser light diffraction permits to extract
some information on the array structure and represents an interesting
complement to electron microscopy.Comment: accept\'e pour publication \`a Annales de Physique- proceedings of
COLOQ1
Modeling Commercial Processes and Customer Behaviors to Estimate the Diffusion Rate of New Products
We propose a formal model for describing commercial processes and customer behaviors in order to estimate the diffusion rate of new products among time
Statistics of Solar Wind Electron Breakpoint Energies Using Machine Learning Techniques
Solar wind electron velocity distributions at 1 au consist of a thermal
"core" population and two suprathermal populations: "halo" and "strahl". The
core and halo are quasi-isotropic, whereas the strahl typically travels
radially outwards along the parallel and/or anti-parallel direction with
respect to the interplanetary magnetic field. With Cluster-PEACE data, we
analyse energy and pitch angle distributions and use machine learning
techniques to provide robust classifications of these solar wind populations.
Initially, we use unsupervised algorithms to classify halo and strahl
differential energy flux distributions to allow us to calculate relative number
densities, which are of the same order as previous results. Subsequently, we
apply unsupervised algorithms to phase space density distributions over ten
years to study the variation of halo and strahl breakpoint energies with solar
wind parameters. In our statistical study, we find both halo and strahl
suprathermal breakpoint energies display a significant increase with core
temperature, with the halo exhibiting a more positive correlation than the
strahl. We conclude low energy strahl electrons are scattering into the core at
perpendicular pitch angles. This increases the number of Coulomb collisions and
extends the perpendicular core population to higher energies, resulting in a
larger difference between halo and strahl breakpoint energies at higher core
temperatures. Statistically, the locations of both suprathermal breakpoint
energies decrease with increasing solar wind speed. In the case of halo
breakpoint energy, we observe two distinct profiles above and below 500 km/s.
We relate this to the difference in origin of fast and slow solar wind.Comment: Published in Astronomy & Astrophysics, 11 pages, 10 figure
Decreased soluble guanylate cyclase contributes to cardiac dysfunction induced by chronic doxorubicin treatment in mice
Aims: The use of doxorubicin, a potent chemotherapeutic agent, is limited by cardiotoxicity. We tested the hypothesis that decreased soluble guanylate cyclase (sGC) enzyme activity contributes to the development of doxorubicin-induced cardiotoxicity. Results: Doxorubicin administration (20 mg/kg, intraperitoneally [IP]) reduced cardiac sGC activity in wild-type (WT) mice. To investigate whether decreased sGC activity contributes to doxorubicin-induced cardiotoxicity, we studied mice with cardiomyocyte-specific deficiency of the sGC alpha 1-subunit (mice with cardiomyocyte-specific deletion of exon 6 of the sGC alpha 1 allele [sGC alpha 1(-/-CM)]). After 12 weeks of doxorubicin administration (2 mg/kg/week IP), left ventricular (LV) systolic dysfunction was greater in sGC alpha 1(-/-CM) than WT mice. To further assess whether reduced sGC activity plays a pathogenic role in doxorubicin-induced cardiotoxicity, we studied a mouse model in which decreased cardiac sGC activity was induced by cardiomyocyte-specific expression of a dominant negative sGC alpha 1 mutant (DNsGC alpha 1) upon doxycycline removal (Tet-off). After 8 weeks of doxorubicin administration, DNsGC alpha 1(tg/+), but not WT, mice displayed LV systolic dysfunction and dilatation. The difference in cardiac function and remodeling between DNsGC alpha 1(tg/+) and WT mice was even more pronounced after 12 weeks of treatment. Further impairment of cardiac function was attenuated when DNsGC alpha 1 gene expression was inhibited (beginning at 8 weeks of doxorubicin treatment) by administering doxycycline. Furthermore, doxorubicin-associated reactive oxygen species generation was higher in sGC alpha 1-deficient than WT hearts. Innovation and Conclusion: These data demonstrate that a reduction in cardiac sGC activity worsens doxorubicin-induced cardiotoxicity in mice and identify sGC as a potential therapeutic target. Various pharmacological sGC agonists are in clinical development or use and may represent a promising approach to limit doxorubicin-associated cardiotoxicity
Dicke Coherent Narrowing in Two-Photon and Raman Spectroscopy of Thin Vapour Cells
The principle of coherent Dicke narrowing in a thin vapour cell, in which
sub-Doppler spectral lineshapes are observed under a normal irradiation for a
l/2 thickness, is generalized to two-photon spectroscopy. Only the sum of the
two wave vectors must be normal to the cell, making the two-photon scheme
highly versatile. A comparison is provided between the Dicke narrowing with
copropagating fields, and the residual Doppler-broadening occurring with
counterpropagating geometries. The experimental feasibility is discussed on the
basis of a first observation of a two-photon resonance in a 300 nm-thick Cs
cell. Extension to the Raman situation is finally considered
Modeling Commercial Processes and Customer Behaviors to Estimate
We propose a formal model for estimating the diffusion rate of a new product on a coherent market. Our approach is based on a discrete probabilistic modeling of customer behaviors and of commercial processes
- …
