674 research outputs found
On the nature of spatiotemporal light bullets in bulk Kerr media
We present a detailed experimental investigation, which uncovers the nature
of light bullets generated from self-focusing in a bulk dielectric medium with
Kerr nonlinearity in the anomalous group velocity dispersion regime. By high
dynamic range measurements of three-dimensional intensity profiles, we
demonstrate that the light bullets consist of a sharply localized
high-intensity core, which carries the self-compressed pulse and contains
approximately 25% of the total energy, and a ring-shaped spatiotemporal
periphery. Sub-diffractive propagation along with dispersive broadening of the
light bullets in free space after they exit the nonlinear medium indicate a
strong space-time coupling within the bullet. This finding is confirmed by
measurements of spatiotemporal energy density flux that exhibits the same
features as stationary, polychromatic Bessel beam, thus highlighting the
physical nature of the light bullets
Dynamical Casimir Effect in Optically Modulated Cavities
Cavities with periodically oscillating mirrors have been predicted to excite
photon pairs out of the quantum vacuum in a process known as the Dynamical
Casimir effect. Here we propose and analyse an experimental layout that can
provide an efficient modulation of the effective optical length of a cavity
mode in the near-infrared spectral region. An analytical model of the dynamical
Casimir emission is developed and compared to the predictions of a direct
numerical solution of Maxwell's equations in real time. A sizeable intensity of
dynamical Casimir emission is anticipated for realistic operating parameters.
In the presence of an external coherent seed beam, we predict amplification of
the seed beam and the appearance of an additional phase-conjugate beam as a
consequence of stimulated dynamical Casimir processes.Comment: 6 pages, 5 figure
Extreme Events in Resonant Radiation from Three-dimensional Light Bullets
We report measurements that show extreme events in the statistics of resonant
radiation emitted from spatiotemporal light bullets. We trace the origin of
these extreme events back to instabilities leading to steep gradients in the
temporal profile of the intense light bullet that occur during the initial
collapse dynamics. Numerical simulations reproduce the extreme valued
statistics of the resonant radiation which are found to be intrinsically linked
to the simultaneous occurrence of both temporal and spatial self-focusing
dynamics. Small fluctuations in both the input energy and in the spatial phase
curvature explain the observed extreme behaviour.Comment: 5 pages, 5 figures, submitte
The psychometric properties of the Italian adaptation of the Health Orientation Scale (HOS)
Background: A novel approach suggested that cognitive and dispositional features may explain in depth the health behaviors adoption and the adherence to prevention programs. The Health Orientation Scale (HOS) has been extensively used to map the adoption of health and unhealthy behaviors according to cognitive and dispositional features. Coherently, the main aim of the current research was to assess the factor structure of the Italian version of the HOS using exploratory and confirmatory factor analysis and testing the construct validity of the scale by assessing differences in health orientations between tobacco cigarette smokers and nonsmokers. Method: The research protocol was organized in two studies. Study 1 evaluated the dimensionality of the HOS in a sample of Northern Italian healthy people. Three hundred and twenty-one participants were enrolled; they were 229 women (71.3%) and 92 men (28.7%). In Study 2, the factor structure and construct validity of the HOS Italian version was assessed trough confirmatory factor analysis using a tobacco cigarette smokers and nonsmokers population. Two hundred and nineteen participants were enrolled; they were 164 women (75.2%) and 55 men (24.8%). Results: In Study 1, a seven factors solution was obtained explaining 60% of cumulative variance instead of 10 factors solution of the original version of the HOS. In Study 2, the factor structure of the Italian version of the HOS was confirmed and applied to the smokers and nonsmokers; nonsmokers reported higher values than smokers in Factor 1 (MHPP) [t (208) = - 2.739 p <.007] (CI 95-4.96% to -.809), Factor 2 (HES) [t (209) = - 3.387 p <.001] (CI 95-3.93% to -. 1.03), Factor 3 (HIC) [t(213) = - 2.468 p <.014] (CI 95-2.56% to -.28) and Factor 7 (HEX) [t(217) = - 3.451 p <.001] (CI 95%- 1.45 to.39). Conclusions: Results of the Italian adaptation of HOS lead to a partial redistribution of items and confirmed 7 subscales to distinguish psycho-cognitive dispositional dimensions involved in health orientation styles
The psychometric properties of the Italian adaptation of the Health Orientation Scale (HOS)
Background: A novel approach suggested that cognitive and dispositional features may explain in depth the health behaviors adoption and the adherence to prevention programs. The Health Orientation Scale (HOS) has been extensively used to map the adoption of health and unhealthy behaviors according to cognitive and dispositional features. Coherently, the main aim of the current research was to assess the factor structure of the Italian version of the HOS using exploratory and confirmatory factor analysis and testing the construct validity of the scale by assessing differences in health orientations between tobacco cigarette smokers and nonsmokers. Method: The research protocol was organized in two studies. Study 1 evaluated the dimensionality of the HOS in a sample of Northern Italian healthy people. Three hundred and twenty-one participants were enrolled; they were 229 women (71.3%) and 92 men (28.7%). In Study 2, the factor structure and construct validity of the HOS Italian version was assessed trough confirmatory factor analysis using a tobacco cigarette smokers and nonsmokers population. Two hundred and nineteen participants were enrolled; they were 164 women (75.2%) and 55 men (24.8%). Results: In Study 1, a seven factors solution was obtained explaining 60% of cumulative variance instead of 10 factors solution of the original version of the HOS. In Study 2, the factor structure of the Italian version of the HOS was confirmed and applied to the smokers and nonsmokers; nonsmokers reported higher values than smokers in Factor 1 (MHPP) [t (208) = - 2.739 p <.007] (CI 95-4.96% to -.809), Factor 2 (HES) [t (209) = - 3.387 p <.001] (CI 95-3.93% to -. 1.03), Factor 3 (HIC) [t(213) = - 2.468 p <.014] (CI 95-2.56% to -.28) and Factor 7 (HEX) [t(217) = - 3.451 p <.001] (CI 95%- 1.45 to.39). Conclusions: Results of the Italian adaptation of HOS lead to a partial redistribution of items and confirmed 7 subscales to distinguish psycho-cognitive dispositional dimensions involved in health orientation styles
Osterix-cre marks distinct subsets of CD45- and CD45+ stromal populations in extra-skeletal tumors with pro-tumorigenic characteristics
Cancer-associated fibroblasts (CAFs) are a heterogeneous population of mesenchymal cells supporting tumor progression, whose origin remains to be fully elucidated. Osterix (Osx) is a marker of osteogenic differentiation, expressed in skeletal progenitor stem cells and bone-forming osteoblasts. We repor
Coherent metamaterial absorption of two-photon states with 40% efficiency
Multiphoton absorption processes have a nonlinear dependence on the amplitude of the incident optical field, i.e., the number of photons. However, multiphoton absorption is generally weak and multiphoton events occur with extremely low probability. Consequently, it is extremely challenging to engineer quantum nonlinear devices that operate at the single photon level and the majority of quantum technologies have to rely on single photon interactions. Here we demonstrate experimentally and theoretically that exploiting coherent absorption of
N
=
2
NOON states makes it possible to enhance the number of two-photon states that are absorbed by at most a factor of 2 with respect to a linear absorption process. An absorbing metasurface placed inside a Sagnac-style interferometer into which we inject an
N
=
2
NOON state, exhibits two-photon absorption with
40.5
%
efficiency, close to the theoretical maximum. This high probability of simultaneous absorption of two photons holds the promise for applications in fields that require multiphoton upconversion but are hindered by high peak intensities
Dynamic Collection Scheduling Using Remote Asset Monitoring: Case Study in the UK Charity Sector
Remote sensing technology is now coming onto the market in the waste collection sector. This technology allows waste and recycling receptacles to report their fill levels at regular intervals. This reporting enables collection schedules to be optimized dynamically to meet true servicing needs in a better way and so reduce transport costs and ensure that visits to clients are made in a timely fashion. This paper describes a real-life logistics problem faced by a leading UK charity that services its textile and book donation banks and its high street stores by using a common fleet of vehicles with various carrying capacities. Use of a common fleet gives rise to a vehicle routing problem in which visits to stores are on fixed days of the week with time window constraints and visits to banks (fitted with remote fill-monitoring technology) are made in a timely fashion so that the banks do not become full before collection. A tabu search algorithm was developed to provide vehicle routes for the next day of operation on the basis of the maximization of profit. A longer look-ahead period was not considered because donation rates to banks are highly variable. The algorithm included parameters that specified the minimum fill level (e.g., 50%) required to allow a visit to a bank and a penalty function used to encourage visits to banks that are becoming full. The results showed that the algorithm significantly reduced visits to banks and increased profit by up to 2.4%, with the best performance obtained when the donation rates were more variable
Biological effects of EF24, a curcumin derivative, alone or combined with mitotane in adrenocortical tumor cell lines
Background: Curcumin has numerous properties and is used in many preclinical conditions, including cancer. It has low bioavailability, while its derivative EF24 shows enhanced solubility. However, its effects have never been explored in adrenocortical tumor cell models. The efficacy of EF24 alone or combined with mitotane (reference drug for adrenocortical cancer) was evaluated in two adrenocortical tumor cell lines, SW13 and H295R. Method and Results: EF24 reduced cell viability with an IC50 (half maximal inhibitory concentration) of 6.5 \ub1 2.4 \ub5M and 4.9 \ub1 2.8 \ub5M for SW13 and H295R cells, respectively. Combination index (EF24 associated with mitotane) suggested an additivity effect in both cell lines. Cell cycle analysis revealed an increase in subG0/G1 phase, while motility assay showed a decrease in migratory cell capacity, and similarly, clonogenic assay indicated that EF24 could reduce colony numbers. Furthermore, Wnt/\u3b2-catenin, NF-\u3baB, MAPK, and PI3k/Akt pathways were modulated by Western blot analysis when treating cells with EF24 alone or combined with mitotane. In addition, intracellular reactive oxygen species levels increased in both cell lines. Conclusion: This work analyzed EF24 in adrenocortical tumor cell lines for the first time. These results suggest that EF24 could potentially impact on adrenocortical tumors, laying the foundation for further research in animal models
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