1,323 research outputs found
Topological signature of deterministic chaos in short nonstationary signals from an optical parametric oscillator
Although deterministic chaos has been predicted to occur in the triply
resonant optical parametric oscillator (TROPO) fifteen years ago, experimental
evidence of chaotic behavior in this system has been lacking so far, in marked
contrast with most nonlinear systems, where chaos has been actively tracked and
found. This situation is probably linked to the high sensitivity of the TROPO
to perturbations, which adversely affects stationary operation at high power.
We report the experimental observation in this system of a burst of irregular
behavior of duration 80 microseconds. Although the system is highly
nonstationary over this time interval, a topological analysis allows us to
extract a clearcut signature of deterministic chaos from a time series segment
of only 9 base cycles (3 microseconds). This result suggests that
nonstationarity is not necessarily an obstacle to the characterization of
chaos
An ex-post view of inequality of opportunity in France and its regions
This paper proposes an ex-post measure of inequality of opportunity in France and its regions by assessing the inequality between individuals exerting the same effort. To this end, we define a fair income that fulfils ex-post equality of opportunity requirements. Unfairness is measured by an unfair Gini based on the distance between the actual income and the fair income. Our findings reveal that the measures of ex-post inequality of opportunity largely vary across regions, and that this is due to di_erences in reward schemes and in the impact of the non responsibility factors of income. We find that most regions have actual incomes closer to fair incomes than to average income, excepted Ile de France where the actual income looks poorly related to effort variables. Finally, we find that income inequality and inequality of opportunity are positively correlated among regions
Oscillations in the expression of a self-repressed gene induced by a slow transcriptional dynamics
We revisit the dynamics of a gene repressed by its own protein in the case
where the transcription rate does not adapt instantaneously to protein
concentration but is a dynamical variable. We derive analytical criteria for
the appearance of sustained oscillations and find that they require degradation
mechanisms much less nonlinear than for infinitely fast regulation.
Deterministic predictions are also compared with stochastic simulations of this
minimal genetic oscillator
Oscillations in the expression of a self-repressed gene induced by a slow transcriptional dynamics
We revisit the dynamics of a gene repressed by its own protein in the case
where the transcription rate does not adapt instantaneously to protein
concentration but is a dynamical variable. We derive analytical criteria for
the appearance of sustained oscillations and find that they require degradation
mechanisms much less nonlinear than for infinitely fast regulation.
Deterministic predictions are also compared with stochastic simulations of this
minimal genetic oscillator
Mode hopping strongly affects observability of dynamical instability in optical parametric oscillators
Theoretical investigations of dynamical behavior in optical parametric
oscillators (OPO) have generally assumed that the cavity detunings of the
interacting fields are controllable parameters. However, OPOs are known to
experience mode hops, where the system jumps to the mode of lowest cavity
detuning. We note that this phenomenon significantly limits the range of
accessible detunings and thus may prevent instabilities predicted to occur
above a minimum detuning from being evidenced experimentally. As a simple
example among a number of instability mechanisms possibly affected by this
limitation, we discuss the Hopf bifurcation leading to periodic behavior in the
monomode mean-field model of a triply resonant OPO and show that it probably
can be observed only in very specific setups.Comment: submitted to Phys. Rev.
Comprehensive annotation and evolutionary insights into the canine (Canis lupus familiaris) antigen receptor loci
Dogs are an excellent model for human disease. For example, the treatment of canine lymphoma has been predictive of the human response to that treatment. However, an incomplete picture of canine (Canis lupus familiaris) immunoglobulin (IG) and T cell receptor (TR) - or antigen receptor (AR) - gene loci has restricted their utility. This work advances the annotation of the canine AR loci and looks into breed-specific features of the loci. Bioinformatic analysis of unbiased RNA sequence data was used to complete the annotation of the canine AR genes. This annotation was used to query 107 whole genome sequences from 19 breeds and identified over 5,500 alleles across the 550 genes of the seven AR loci: the IG heavy, kappa, and lambda loci; and the TR alpha, beta, gamma, and delta loci. Of note was the discovery that half of the IGK variable (V) genes were located downstream of, and inverted with respect to, the rest of the locus. Analysis of the germline sequences of all the AR V genes identified greater conservation between dog and human than mouse with either. This work brings our understanding of the genetic diversity and expression of AR in dogs to the same completeness as that of mice and men, making it the third species to have all AR loci comprehensively and accurately annotated. The large number of germline sequences serves as a reference for future studies, and has allowed statistically powerful conclusions to be drawn on the pressures that have shaped these loci.This work was supported by funding from the BBSRC and the Wellcome Trust
Evolution of the T-cell receptor (TR) Loci in the adaptive immune response: The tale of the TRG locus in mammals
T lymphocytes are the principal actors of vertebrates’ cell-mediated immunity. Like B cells, they can recognize an unlimited number of foreign molecules through their antigen-specific heterodimer receptors (TRs), which consist of αβ or γδ chains. The diversity of the TRs is mainly due to the unique organization of the genes encoding the α, β, γ, and δ chains. For each chain, multi-gene families are arranged in a TR locus, and their expression is guaranteed by the somatic recombination process. A great plasticity of the gene organization within the TR loci exists among species. Marked structural differences affect the TR γ (TRG) locus. The recent sequencing of multiple whole genome provides an opportunity to examine the TR gene repertoire in a systematic and consistent fashion. In this review, we report the most recent findings on the genomic organization of TRG loci in mammalian species in order to show differences and similarities. The comparison revealed remarkable diversification of both the genomic organization and gene repertoire across species, but also unexpected evolutionary conservation, which highlights the important role of the T cells in the immune response
Cooperative oscillation of non-degenerate transverse modes in an optical system: multimode operation in parametric oscillators
We show experimentally that parametric interaction can induce a cooperative
oscillation of non simultaneously resonant transverse modes in an optical
parametric oscillator. More generally, this effect is expected to occur in any
spatially extended system subjected to boundary conditions where nonlinear wave
mixing of two nonresonant spatial modes can generate a resonant oscillation
Appeal No. 0714: Gary Harris & Group Maintenance v. Division of Mineral Resources Management
Chief\u27s Order 2003-1
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